Well, it wont hurt if you try - if the game gets unstable, dial back the effects.
Also if you have Nvidia their laters (maybe beta) drivers allow for FSAA on any game - but it messes the fonts.
Update - tested FSAA on my nvidia GTS 450, seems to be working fine, font edges get a little blurry (expected), but only a little. Overall an improvement, I'll keep it on.