Ok, I looked at all my games for the PS2 and look what I noticed:
1. Konami (6 games) (Shadow of Memories, Ring of red, Pro evolution soccer, Zone Of Enders, Silent Hill 2, ESPN Int. Track & Field)
2 Electronic Arts (2 games) (SSX, SSX tricky)
3. SEGA (Crazy taxi), PD (GT3), Naughty Dog (Jak and Daxter), SB studios (Baldurs Gate)
Then there is a tons of games that i have bought and sold.
But Konami is totally superior on my chart. And soon you can add MGS2 on that list.
Please post your lists.