I used Movie Maker for a LONG time, but there are two things you DEFINITLY have to keep in mind.
1: HD. If the new camera you got is HD, then it WILL NOT work with Movie Maker without a BIG fight. I do NOT reccomend it at ALL.
2: WindowsXP. I dunno if they have changed it by now, but back when I used it on XP, it was almost impossible to use WMM to make anything decent because of some of the tools. This was later corrected in the version that came with Vista, so maybe there is a free download. The Vista version had a LOT better stuff you could do AND it was WAY easier.
So, I highly reccomend Windows Movie Maker if you don't need SUPER proffesional looking stuff, aren't editing HD and can get the version that for me, came with Vista.
Other than that, I agree with the Vegas thing. GREAT software, if you have the money. Vegas Movie Studio is a cheap alternative.
Hope that helps! If you have any more questions, feel free to post them or PM me if you want!