laney vc15/30 (there's no 20, unfortunately, you need to decide if you can cope with 10 extra watts, or 5 less, than your ideal amount- though th 30 has a 12" speaker compared to the 15's 10"- that might swing the deal on its own). the lc15 or 30 might be worth a look too, though I prefer the vc (that's preference, though).
Fender blues junior (15 watts).
Peavey classic 30.
I guess a vox ac15 might be worth a try too.
Matamp might make some in that price range, i'm not sure though. If they do, they're worth a look.
remember to try them cranked up too- some that might sound on equal par at low volumes may not be at full whack (*cough* peavey classic 30, laney lc, which both sound less than amazing up full *cough*)
That's about all I can think of off-hand, it's mainly preference as to which you prefer, so you'd ideally need to try them. There are probably some glaring omissions there too, I normally manage to forget the "usual suspects" in any price range.
