Hi there! Perhaps you will find the following programs quite helpful. I use Adobe Aftereffects, it's awesome:http://www.adobe.com/products/aftereffects.html
Adobe Premiere is cool too, it comes with lots of options and effects:http://www.adobe.com/products/premiere.html
However, Movie Maker is the easy-to-use powerful app. What do you dislike about it? It may be possible that you use it wrong or don't fully comprehend its functioning principle. I use Movie Maker and find the results satisfying. Check out this guide http://www.askwiki.net/How-to-Use-Windows-Movie-Maker
to start using Movie Maker effectively.