The Studio 20's are great, but I'm not sure if they'll work so well in a room that big. You may find yourself wanting a sub to fill out the low end. It's tough to choose between a higher end bookshelf and a lower end tower that would generally give you more bass. Of course I have to plug my own Studio 40 V.2s which are a bit more bassy than the V3s. You might be able to find them used at a pretty good price. They sound quite good (imo) for a <$1000/pr speaker, have plenty of muscle and are certainly acceptable without a sub.

If you want something exotic, you could try to Magnepan MMGs. ($550/pr Retail)

Another choice that will give you spread out sound and decent bass are Definitive Technology BP6Bs ($600/pr Retail). I'm not a huge Def Tech fan, but if you like the sound, they are a pretty good value for the money.