It depends on the genre. If it's a first person shooter, minimum is 25-30 (smooth). If it's a fast paced action game then the same holds. Games like Skyrim I can make do with 25 minimum. Strategy games can dip to 20 but higher is always nicer. --- Genius has its limitations. Ignorance has none.
Anything less than 60 is unplayable. The more the better. 120 would be ideal but the current so called ips screens don't support that. --- The purpose of my life is to play games. Its the reason I even work.
30 is tolerable. Lower, not so much, unless it's somewhere like in a WvW map zerg fight in GW2, in which case expecting it to not go below 30 will result in quite a bit of disappointment. --- HAF 912 | i3-3220 @ 3.3 GHz | SAPPHIRE HD 7850 2 GB OC Edition | Corsair CX430 | 8 GB Corsair XMS3 1600 | Seagate Barracuda 2 TB | MSI B75MA-P45 | Win 8x64