I did a lot of reasearch before buying Sony Vegas Movie Studio 9, and it appeared that the best programs for a novice while still being powerful are Movie Studio 9 and Cyberlink PowerDirector 7. As mentioned in another thread, you need newer hardware for PowerDirector, though (i.e. an nVidia card with CUDA, so 8xxx or newer).

There is a learning curve with Movie Studio, as with anything new, but Sony has tutorial videos on their site which are actually very good, as well as text tutorials built in to the software that run with your actual project, so you are using a real example while learning. Sony even has forums on their own site, too.

My personal opinion would be to download the free trials of both Movie Studio 9 (not Vegas Pro) and PowerDirector 7 and try them for yourself. They are fully functional (I believe) for 30 days, so you can still use the tutorials and such in the trial versions.

The fact that you are even asking on this forum makes me think you have already outgrown Windows Movie Maker, but I am not a fan of that application to start with.