Based on ownership and enjoyment for me personally:
1. Xbox 360
2. Megadrive
3. Gamecube
4. PS2
5. SNES
Apologies but I was a Sega fanboy hence the SNES below Megadrive. 360 on top because I love FPS games. The PS3 hasn't had much gaming time from me due to the fact I buy multiplats on 360 and my Wii didn't make the list because I can't be bothered playing it anymore (my loss I guess). PS2 made the list for the hours spent on Guitar Hero 1 and 2. Gamecube gave me many hours fun last gen and was the first console I bought from that generation.