A place to recharge, and keep clear of the clutter. Maybe with security. Gentle, mindful security.
Jory: A meditation room, or a room where b-friend could put all of his knick-knacks.
Karen: A studio/meditation room. That only *I* had access to. And it would give everyone else a mild electrical shock if they tried to get in.

Like Grace's Menopausal Hut, but with better security and more staff.
Baseballmom: It's a toss-up, either a large, soundproof playroom with a locking steel door, or a large soundproof spa room with a hot tub, and a professional masseuse and pedicurist (ummm, is that a word?).
Margalit Topaz: Mommy's spa room, complete with sauna, huge whirlpool bath, a pedicure chair, and those tubs of hot paraffin that you put your hands and feet into to make them smooth as silk. There would be a fridge stocked with champagne and boxes of chocolates would abound. Of course, a large plasma screen and DVD player so mommy could veg out in the whirlpool watching movies. The room would have a huge combination lock on the door with alarms and motion detectors so nobody but mommy ever gets to enter the room.
Nicole: A sound-proofed, dead-bolted secret room stocked with chai latte, fresh fruit, and quality chocolate. Add in a wireless connection, a laptop, some good books and a flushing toilet, and I could stay for days.
Pamalamadingdong: My very own private washroom with high tech security that will NOT permit children under any circumstances while am sitting on the throne. Also? KNOCK PROOF doors.
Susan: One of those fancy walk-in dressing room closets, with a nice chaise lounge and a television and a mini-refridgerator (it's not so much that I'm into clothes, it's just that I'm tired of crouching in the coat closet when I need to hide from my kids).
Carmen: A room just for me. No one else could enter.
Holli: This seems to be a repetitive theme, if you read one of my "Turkey Talk" answers.. but I would like a fully staffed spa, open 24/7. There's no such thing as too much massage. If you have evidence to prove otherwise, send it elsewhere.. a girl's gotta have dreams.
Jenijen: A giant craft, laundry, library area. Mandatory skylight, tile floors, big windows, NO CHILDREN'S TOYS, a big comfy soft chair and ottoman. Wet bar. Lock on door. Spa. Personal massuse. Chocolate. Person to do the laundry.
hadashi: mmm, the big spa/solarium room that includes a lap pool, steam room, a jacuzzi, a full-time masseur/masseuse, big fluffy robes and super comfy lounge chairs. yeah...
EverydaySuperGoddess: Mom’s quiet room. With lots of places where I can hide the cookies and a door that locks from the inside.
Just Dawn: A room with a hot tub. I actually dont even need the ""room"" just need the hot tub. ohhhh...my back feels better already.

Whee! I can't decide, but I'm going all out!
Mindy: A dungeon with tiny Iron Maidens. The spikes can be dull and flexible. No—a safe room. No—a padded room. No—a trampoline room. No! A fully-staffed spa room! With Jacuzzi! And bikini waxes! And drinks that can sit on the floor so you can sip through long straws while face-down on the massage table being pounded senseless by a big man named Olaf.

No, no more for me, thanks. I'm thinking about downsizing. To the French Riviera.
Amber…bamberbooMy house is too big already! I can never get the whole house clean in one day, so.... can I just have a little apartment in the French Riviera instead? Pleeeeeeeaze?

Rolling Staircases! Yeah!
Ann Douglas: A library. Not a room called a library—a full-sized library.
Eulallia: A library, with walls and walls of books, and one of those rolling ladders that attaches to the wall. That is my ultimate dream.
Jen Lawrence: A library. A two story one. With those wooden stair things that slide around the shelves.

I'd like a room in another dimension, please.
Krisco: Um, like a really, really big room that encompasses a
whole new house? Or a whole new top floor that would utilize the view we theoretically have from this hill?
Or maybe a room with a really cool super escalator, like that one they are talking about making for space,
that would zoom me to a real, happening, things-going-on city? Or – maybe one in which my kids
would magically fall asleep on time, and sleep through the night, so that we could actually utilize the rooms
we already have, or at least pick them up? Wait a minute, maybe I’m thinking too wacky here. Maybe you
meant, like, “bath”. I think I need more clarification on the question.

Just a little personal space here, mmkay?
Sleepless Mama: Another bedroom for me and Bizarro Dad, so we'd no longer have to share a room with the kids, since obviously my brother is never going to move out and get a job and a place of his own. (No, I'm not bitter. Why do you ask?) Then later, when he does finally get booted out or shuffled off to another relative, I can use the extra room as my own personal library. I'm running out of room to put shelves in the living room.
Jordana: Another bedroom! We have three small bedrooms, which get crowded quickly for this family of five.
Dawn: An extra bathroom for Mommy only. I just want some quiet time, that’s all. I don’t want to answer any questions while ensconced on the “throne”. I want less to answer questions of a “Lady Nature” while ensconced.
Justice: a sound-proofed bathroom! (so I can beautify in peace)
DaniGirl: This one was easy. I just blogged about it the other day. If I could, I'd add on my very own bedroom. Why do we forever give up the right to our own bed when we get married? I'm content to share many things, but I really would love a bed of my own, and if we're adding entire rooms, might as well have a room of my own, too. Scrap that, I love my bedroom, I'd build an extra bedroom for Beloved and keep ours for myself.
la Mala: It's a tie. I share a bedroom with my daughter so my own bedroom so I could um entertain ::wink wink:: more would be nice. I would also like a real office instead of working from the hallway that leads to the bathroom.
Tonya: A really luxurious master bath with a tub deep enough to cover my belly even now when I am pregnant. That is on the list for the next house.
Clickmom: sauna
Sabrina: OMG we need a 2nd bathroom. I'm so dreading as we continue to potty train here having 5 of us using the one bathroom we have.

A private workspace
Sour Duck: A pc room. Do you know how hard it is to blog from the bathroom? I'm living like a dormouse here!"
Elisa Camahort: An office. Right now I work in the corner of my dining room, wedged between the table and the window
Lauren: An office. I would love a place where I can play on my computer with a desk and chair as opposed to simply sitting in bed all day.
Melanie Lynne Hauser: An office, an office - my kingdom for an office!

For the plants
Emily G: A sunroom for plants. My plants are suffering at the hands of a cold, cold house in the north where the light gets thin in the winter and the cloud cover is pretty constant.
Charity: A sun room.

Hah! Mommybloggers love optimists!
Graceful: A workout room. That way I could actually work out!

I'm going to say yes.
Busy Mom: Garage. Is a garage a "room"?

It's all about comfort, I think.
MoMMY: A padded one.
Lucinda: A rubber room, of course. They're all the rage right now in Architectural Digest.

More storage, please!
mazeway: I often have this dream in which I discover a room in my house that I never knew was there. Given that I live in a 1903 bungalow, I would turn that surprise room into a big ol' closet. Because apparently Edwardian people bought new clothes, linens, and food everyday and then threw them away before bed.
Tuesday Girl: I would add onto my existing family room. You know, to accommodate all the toys you swore would never litter your house and you would contain them so nobody would ever think you even had kids. Yeah right.
Jenny: I would love an old fashioned attic with dormer windows and creaky wood floors. So I could fill it up with crap, no doubt.
Beth: Storage. How boring, I know, but the curse of townhouse living.

Indeed.
Tiiana: Room? Why just a room? What about a house?!?

Extreme Makeover- Fantasy Island
Erin: Maid's Quarters. Of course, then, we'd have to hire a maid.
Meghan: A room to make soup in. Only soup. It would be the soup room, and if I don't like you I can say "NO! NO SOUP FOR YOU!" and then slam the door.
Desperate To Be A Housewife: A Parlor. I've always wanted to have a "no children in the Parlor" rule...but then I'd need a British accent to go with...
Colin: It would be a room designed specifically for parties and get togethers with all the things needed for this kind of thing and of course a huge discoball.
Jamie: An upstairs laundry room. Floodproof (in an old apartment we once had a flood from an upstairs washing machine) and with an antigravity laundry chute to whisk up the downstairs laundry.
Allison: a brig with one of those slide throughs for meal trays
Susie Sunshine: A full size gymnasium with bleachers.
Four boys + Long Michigan winters = Cabin Fever of Epic Proportions