Term limits = good. Encourages change within the two party system. Otherwise, the incumbent party will just continue nominating its incumbent candidate... if I don't like that incumbent, I have to vote for a totally different party.
I would vote Republican, but not as long as GWB is their presidential nominee. As much as I think the democratic party is a rudderless garbage scow drifting in a river of crap, I can't bring myself to vote for George. However, the Repubs have lots of good leaders that I would love to have the opportunity to vote for. Without term limits, they might never get a chance to make it past the primary.
If we didn't have an 8 year cap, I think the country would get into a "well he didn't screw things up too bad (and I'm too lazy to go research issues and I recognize this guy's name), so I'll vote for him again" mentality. I personally believe that change is good because diversity of views is such a fundamental part of democratic society. You'd lose a lot of that diversity of thought if you had the same president for too long.