ITT: We list every Sega game ever made.
For real though my short-list would be:
Virtua Fighter 5: Final Showdown - So I don't need to buy a console for one game. Fighting games on PC are always wonderful, and this would be the ONLY 3D fighter on PC that I can think of. Tekken isn't there, SC isn't there and neither is DoA.
Anarchy Reigns - For the chance that Multiplayer might be relived somewhat instead of DOA on consoles outside of Japan/NA.
Vanquish - Just a top game.
Bayonetta - Just the toppest game. (Also why is there still massive slowdown on the Wii-U version? Get it together Nintendo, Jesus...)
Yakuza Collection - Probably never happen because of some deal Sega made in a back-room with Sony involving a knife and burning a picture of a saint, but this would be ideal, backwards compatibility forever and no need to own Sony consoles if you don't already. Not least of all because some clever dick would probably mod in English subtitles for Yakuza 5.
Metal Gear Solid Series - Oh wait...