I don't really know I usually choose the best games for any system I own just to save on money.
PS2
1.Soul Calibur 3
2.Devil May Cry series
3.Resident Evil Outbreak
4.Resident Evil 4
5.Tekken 5
DS
1. One Piece Gear Spirit
2. Elite Beat Agents
3. Mario Kart DS
4. Resident Evil Deadly Silence
5. Pheonix Wright Ace Attorney
Wii
1.Resident Evil Umbrella Chronicles
2.Rayman Raving Rabbids
3.Rayman Raving Rabbids TV Party
4.Star Wars The Force Unleashed
5.The Beatles Rock Band
Xbox 390
1.Marvel Ultimate Alliance Gold Edition
2.Devil May Cry 4 (Collector's Edition)
3.Resident Evil 5
4.Halo 3 ODST
5.Soul Calibur 4
PC
1.Half-Life
2.Half-Life Oppossng Force
3.Half-Life Blue Shift
4.Half Life 2 (including episode 1 and 2)
5.Star Craft Brood War Expansion