If you have a modded or import PS2 there is a chance for some decent ports, and that old style joystick for a more neo feel too. They are soon to release in Japan KoF collections. KoF 94 was already released with both a remastered version and the original, 95-98, then 99-01 are coming as collectors sets, 2000/01 are already out in the states and 02/03 are set to come out as well. There is also word of MotW and a Last Blade 1 and 2 set. With all this in mind I have been very tempted to buy an import PS2.
I have also heard very promising things about SF AC on ps2. Now, I am not a tourney level player on that game, but those that are say the DC version has a touch of lag that causes problems when you do difficult parries like an entire alpha string, but the ps2 is evidentally fixed in that regard.
Unfortunately, I would avoid Sam Sho on any system asside from the Neo though. Maybe its the size of the spirtes, but for some reason those games are burdened with abysmal loading times. Some suggest that if you get Sam Sho 5 for PS2 and a HD loader kit so you can copy it to the HD rather than playing it from the disc it is much better, but those same people tend to say you have to do it in a roundabout fashion because SS5 doesn't work if you just copy it to the HD.
The only other major game I can think of you can get as a port is Real Bout which has a collection for the Saturn that came out very good. The only reason I sold it was because at the time I had a deal for Real Bout 2 and it was similar enough to RB special (some say the best game in the series) with an extra 2 characters in it. If you have a Saturn, like 2d fighters, and don't have them on the AES/MVS the Real Bout collection is a must own.
As for the DC the above poster is correct, KoF Evo (99)-02 are good games, as are the others he mentioned. The only reason I don't put KoF 99 Dream Match (this is KoF 98) in that list is because every time a new character loads in a 3v3 match the music starts over. This may be nitpicky, but damn is it ever annoying. Some matches are over in 30 seconds or less and you get to hear the exact same song start all over sometimes 4 and 5 times in a row. If you can put up with that its fine. Speaking of sound MotW is known to have delayed sound effects. Its nothing drastic, but the hits sound like a half second behind. And then Last Blade 2 has a specific controller mapping that you are limited in your options to change. It only uses the 4 face buttons on the DC controller for the main buttons. The triggers are auto mapped and unchangable. It took me a bit to get used to that configuration after playing it on the Neo so long. Again, I am picky I know.
Hope this all helps.