If you want to upgrade to Ivy Bridge: Z75/Z77 MoBo
If you want to upgrade to Sandy Bridge: P67/Z68
Hint: Some Z68 MoBo's are compatible with Ivy Bridge.
Hint 2: Z75/Z77 MoBo's are compatible with Sandy Bridge
If you want to upgrade to Sandy Bridge: P67/Z68
Hint: Some Z68 MoBo's are compatible with Ivy Bridge.
Hint 2: Z75/Z77 MoBo's are compatible with Sandy Bridge