A CPL is worth buying, and I agree that you should always - well, nearly always - use a lens hood.
UV filters were designed for film photography, and DSLRs don't need them. They will never, and cannot, improve your image quality; but can degrade it. Some people do like to use them to 'protect' the front of the lens, but there have been endless arguments about this. You'll find these on the forums if you do a search.
It's up to you. I don't use protection filters as a rule, and I haven't damaged a lens in + 40 years. I do use one occaisionally, if conditions are rough (blowing sand, spume etc), but it's not a deal breaker for me. If you do want to go down this route, get a quality filter - plain glass is just as good - to reduce the risk of softness and flare. Hoya Pro 1 and B & W get decent reports, but I can't speak from personal experience and others may offer different advice. Mine are Kenko, which I think are manufactured by Hoya, but I bought them in SA where choice is limited and this sort of thing is very expensive.