how big a speaker can you put in an 11 x 11 room?

You should keep the speakers as small as possible and add a sub later only if needed.

I use OHM 100s and Dynaudio monitors in two 12X12 rooms in my house.

The largely omni OHMS work best. They are small footprint full range floorstanders. Being largely omnidirectional, they tend to fill teh room with sound rather than blast it at you, which is of benefit in a small room. They are also less fussy about location for smooth response than box designs in a square room.

OHM Micro Walsh Talls have an even smaller footprint than the 100s and are recommended for nearfield listening conditions as you will have in a room that size.

They can be auditioned in-house for several months. You really have nothing to loose.

www.ohmspeakers.com for more info.

Many British monitors work well in a room that size. Believe me I know, I have a 12' X 11' room.
Much has been discussed here on Audiogon about small rooms. Do a search, you will find plenty of info.
Monitors definately work best, sub not likely needed.
A partial list:

Linn
Spendor
Neat
PMC
Joseph Audio
ERA Designs
Aerial
Audio Note

All of the above make nice monitors that will work

The problem in a small room is low frequency response. A small sealed monitor will work because there won't be a lot of bass. Otherwise, a full-range transmission line speaker will work. You will have bass, although you should have bass traps in a room that small regardless of the speakers, and a TL speaker will be easier to place than a ported full-range speaker. The Salk Sound SongTower or Veracity QWT would be good choices.

no one is talking about the arro from totem, what a geat speaker with such a small footprint and big sound stage and depth....

Great point Dwhitt - Arros are great, especially with Jazz on vinyl, the OP's stated affliction of choice. Would also throw in a suggestion for one of the Kef monitors - I think the XQ series unless you plan to spend way more for the much better Reference. I owned some of their older low end ones and they were pretty amazing for the price in small rooms. Another to consider, is Usher series, they tend to throw a great soundstage in cramped quarters, not an easy feat.