2.4 or ecotec are the 2 swaps id recommend. There is also the 3400, 3800 and 3800 s/c.
Of the swaps previously mentioned. You will have better luck with the 2.4 and Eco (in that order).
The 2.4 is going to be more of a direct bolt in, where as the Eco will need a couple parts fabbed in (so I've read). Both will require replacing the wiring harnesses and ECU.
The 3x00's are possible, but require some research to do so. Check the third gen forum for a writeup (and there's plenty of other threads on it, so the search will help here).
The 2.4 has a diminishing aftermarket since it is now a discontinued engine, replaced by the Eco.
The 3100, 3400 OHV, 3400 DOHC, 3800, and 3800 SC can all be shoved in there. But it takes more work than you'll imagine.
I would definitely go for a 2.4 if I were in your position. The 95 2.3 would be the easiest, but not really very modifiable.
you will need to swap your trans if you put in an eco.