The Alfa MiTo and Giuletta QV models are pretty smart, 170 and 240hp respectively. Not to mention the inevitable GTA models But you'll be paying for the prestige-branded badge on those, of course...
Any particular cars you have in mind? The upcoming Toyota/Subaru FT-86 has me hoping Toyota will relive some of the glory days of the MR2, Supra and early Celicas. The hot-hatch Citroën DS3 is tasty with 150hp and I've heard rumors of a 200+hp rally-inspired model as well. And of course, you've got the Mini Coopers and the hot Renaults and so on.
Who says you can't buy fun cars anymore?
(Says the guy who's just bought a motorcycle because cars in his price range are all dull...)
Trouble is with the Mito, you can't turn off the ESP and from what I've read they don't cut it as drivers cars, so not exciting enough for me really.
I really want around 200bhp. 150bhp won't be enough really. DS3R is interesting. My favourite contender at the moment is the FD2 which is the JDM Civic Type-R in a 4 door saloon shell (youtube FD2 if you want to see what it is). That is 222bhp, but it's so rare I've yet to actually see one. Figuring that when I've paid my car off I can pick one up second hand for 14-15K.
FT-86 sounds good, but it's all speculation and I'll bet the top model doesn't come in at 18K (which would be my limit) but more like 20K+.