During my first two years of teaching we used the Voyager (Universal Literacy) reading program. Each grade level had a theme. 1st grade was the ocean so we all decorated our classrooms to go along with that and it tied directly to our curriculum. Then we got a new reading program (thank goodness) and I've done frogs as my "theme." Since I'm moving up to 2nd grade next year I decided I needed to do a different theme since I'll have some of the same kids so I'm going to do polka dots. And it's just for fun. I enjoy decorating my room and my kids seem to like it too. My former co-workers are a perfect example of this. One of them has so much stuff in her room that it gives me a headache. The other one has an empty room. No color in her room except two bulletin boards that are quite dull. Reminds me of a hospital room. I feel like I'm kinda balanced. I like having pretty colorful things (like my curtains and a few decorative items to go with my theme) but I know my kids with attention problems need some "white space." Do whatever makes you happy. If you can (and want to) do some fun decorative thematic things in you room and still cover you curriculum effectively, I say go for it! If you don't have time or desire, don't worry about it!