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.