Yes most are DVD. A few burn-worthy games are CD (crash 4, marv v capcom 2) but crash 4 looks like a ps1 game, and Marv v Cap 2 is too big to throw on a CDr so you might as well convert it to a dvd game.
Don't burn a CD based PS2 game onto a DVD. There are patching methods, but it screws up the game... And don't burn a DVD based PS2 game onto a CD. Just a simple rule.
Don't forget Crazy Taxi! Of course, that game has such little substance, it is probably a pretty small file size.
Shit, CT is on PS2? Hellz Ya! Thanks for the info. Love the dreamcast game. Is it pretty much the same?
Off-topic, but isn't the Dreamcast the system where you can just burn the disc and pop it in and play it right? Yes, it is.
For the off topic part, not in all cases, you may need to patch the game, as well as over burn...some games are 900mb...and they can't read dvd's.