You can find new models here by looking around. There are also some bufixes and different mod to spice your game up if you want.
The horror in SSH2 wasn't only visual, and the game was already visualy low quality even for its time, but it came from a mix of different elements: feeling of isolation, respawning enemies, low ammo available, dark environments, and last but not leas the audio. The last point is terribly important because you could often hear the enemies before you'd see them but wouldn't know their exact location, and in the case of the hybrids or midwives, their soliloquy is just frightening because it shows that they somehow retain some link to their humanity despite being absorbed by the Many.

The fan made patches are already out there to make this work on Windows 7 64 bit in full resolution widescreen. I played it myself for the first time not so long ago and its still awesome despite being such an old game.
I actually prefer System Shock 1 having said that, apart from the interface which was awful.

I played for the fourth time recently, now as a Psychic Marine, i'm i enjoyed just like the first time. It's fuc**n awesome, and really beat Bioshock in all ways (even graphics, i don't like at all the Ue3 engine). And I spend nearly 12 hours in finish the game!! 12 hours!! Knowing 99% of the secrets...i think that there's only one game that can look in the eyes to SS2, and it's Deus Ex. Sadly, no recent game can at all.

SS2 is at it's best with friends in co-op game. Some of the best games of SS2 I've had with friends.

thought there may be newer versions:
http://www.gnomeslair.com/2007/03/system-shock-2-2k7.html (NSFW)

Wait, 10? Does that mean I have to wait another 8 years before I'm allowed to play with her?

My annelids confirm that is an appropriate time for a birthday.

Yep, you only get to play with her a few years after she comes out, after that it's pedophilia, until 18. :P