Google's Picasa was recommended to me a few years ago, and does almost everything I need (it does not crop circles, though). It does many things Paint doesn't do: it straightens pictures and does color corrections, and it can filter pictures for sepia tone, B&W, etc.

It's free. The downside: it's Google, so it has a natural tendency to want to share all your photos to the web, but this can be disabled.