Canon SLR's are very popular and a good option but they may be outside of your price range. I don't think I've seen them for cheaper than $400. That's what I'm switching too soon. I use a Sony HDR (in your price range) but my model doesn't have a mic input (bad idea) and I want to start using lapel mics.
Check out the Sony HDR's. They are in your price range. Just be sure to choose a model that has a mic input. I really love my camera except for the mic situation. I believe I paid around $300.