I use Ulead Video Studio 10+ for small stuff. It's what I use for making YouTube videos and anything from the camcorder. For harder stuff, I still use my old Vegas Video 3. There's also Pinnacle Studio. I have version 8. But I haven't used it since I bought the Ulead one. Then there's Power Director 3 which came free with my ASUS video card.
Apple bundles iMovie with all Macs. I feel it's a bit better than Windows Movie Maker. Of course, that's not saying much. For heavy duty stuff, there's Final Cut.
I haven't seen a good free video editor besides WMM and iMovie. But if you want a "free" one that's decent, buy a retail ASUS video card with ViVo functions. ASUS normally includes a decent video editor. That's why my last 3 video cards have been ASUS.