This question I saw recently was from G4's "Attack of the Show" and "X-Play". I have my top 10 favorites right here and I feel that they deserve an upgrade to the PS3 (Playstation 3).
1. Final Fantasy VII (PS1) - add voiceovers and deeper stories, real orchestra
2. Rogue Galaxy (PS2) - more mini-games and more costumes
3. Final Fantasy X (PS2) - more mini-games, full version of 'Blitzball'
4. Legend of Legaia (PS1) - english-speaking voiceovers, more casino games
5. Namco Museum (PS2) - more classic arcade games and more unlockables
6. Gottieb's Pinball Hall of Fame Classics (PS2) - more tables and more unlockables
7. Thousand Arms (PS1) - more mini-games and date simulation
8. Sonic's Mega-Collection (PS2) - add Sega CD's 'Sonic CD', plus Saturn's 'Sonic 3-D Blast' and 'Sonic R'
9. Dragon Quest VII (PS1) - 3-D rendered graphics, voiceovers, costumes for all characters, and mini-games
10. Silpheed (PS2) - 3-D rendered graphics, more power-ups, bigger storyline