Personally I always keep a UV filter on every lens as scratch protection if I am not using another filter - if you go anywhere near the sea, it is surprising how quickly salt spray can get onto the lens, very often accompanied by sand. I would say the only time a UV filter is needed for correction purposes is at high altitudes.
I always used to use Hoya filters, no real problems but they do stick easily, the reason is flexing of the aluminum alloy mounts. Also, the design of the polariser mounts is crazy - milling on the front part of the filter, which is easy to grip anyhow, no milling on the rear part which is where it's needed. More recently, I have bought B+W and Heliopan filters directly from Germany, they're really not much dearer and have great brass mounts