lol i seem to be oposite of ulaoulao. I dislike 3d fighters compaired to most compident 2d fighters. Tho I have Not played new ones such as Marvel VS Capcom 3, looks interesting.. apposed to the new Killer Instinct, havn't played, but looks juvinile and childish compaired to the old IMO. KOF2013 and up also looked interesting but never had a chance to play that either.
when i think of PS1, i remember
Twisted Metal
Armored Core
Metal Gear Solid
Ghost in the shell
Tomb raider
Final Fantasy 7 (7only, not other FFs)
Resident Evil
Oddworld
colony wars
gran tourismo (u already metioned)
destruction derby 2
jetmoto
driver
felony1179
some of those may not be great, but i remember them being entertaining when i was young and they were new.
regaurding muli-player, I think almost all the best multiplayer older games were on N64.
For old school fighting games that arn't 3D, I'd just stick with arcade such as winkawaks, for all capcom cps2 neogeo. cps3emu from nebula will do the remaining cps3. u64emu will do kller insctinct 1 and 2. nullDC_100b_1 will do naomi's Marvel VS Capcom 2, good enough, other nullDC versions wont run on older hardware. These can all probably be done with MAME, but mame doesn't run them as fast for older hardware.