Lets see here
NES: 60ish
SNES: 45ish
N64: 50ish
Gamecube: 40ish
Wii: 30ish
GB/GBC: 40ish
GBA: 60ish
DS: 55ish
3DS: 4 (it's new, easy to count)
PS1: 2 (never owned the system)
PS2: 15ish
PS3: 30ish
360: 3 (don't own the system)
PC: 25ish
Total: about 450... sounds right. No idea what percent completed, if I guessed I'd say 75%, somewhere between 300-350.
!!!! Almost forgot my Gamegear! I have 25ish games for that, beaten all of em!
If my grandmother wasn't stupid I'd also have 20 intellivision games but yeah.
NOTE: I never sell games. Someone got me Modern Warfare 2 for Christmas 2 years ago, and I still have it in plastic wrap.
THE JACKEL