UV filters are a waste, unless you are shooting in the desert (Sahara for example). The only filters that are worth anything, IMO, are grad, PL and ND. Everything else, you can do in photoshop.
I agree that graduated ND filters (or reverse, etc) should be the square style. I just ordered a 3 stop SE Galen Rowell filter.
I have never used a UV filter, and I have never had a scratched lens. They are more durable than you think. Just use some lens cleaner, a dedicated lens cloth (hand wash it) and a lens pen, as well as a giottos blower. I have been using these for years and years and years, and never have had a problem. I shoot in the rain and stuff quite a bit, as that is how it is up here.