I've only used it a bit so far, but iMovie appears to meet every basic video editing need except for file types. I'm one of many PC users who switched to Mac largely because of their reputation for excellence, speed and fun in graphic editing, photos and videos especially. I was sorely disappointed to find out that iMovie cannot handle so many standard formats that PC apps handle without thinking. iMovie will import video from your digital video camera, if it's a compatible format, or from a disk it will import DV, MPEG-4 and some .mov formats. That's it.

Quicktime Formats

Ironically not all Quicktime videos (.mov) will open in iMovie, but there is a solution if you have Quicktime Pro (not just the player, you need the for-pay version). If you can open a movie in Quicktime Pro that you want to get into iMovie, "saving" the file as a .mov will not be enough, you'll need to export the movie. Exportimg the Movie to QuickTime Movie was enough to import it into iMovie '09. I would expect that you would have the same success exporting the Movie to MPEG-4 or exporting the Movie to DV Stream, although I haven't tried them. The DV stream will likely produce the best quality.

Note that you can use Quicktime Pro to convert other source video formats as well. Quicktime Pro can open AVI, MPEG-2 and a lot of other formats. Remember however that the more times you convert a video, the more quality you lose. A complete list of formats can be found on Apple's site here.

There are also Mac OS applications you can find with a quick Google search that are supposed to enable multiple formats in iMovie, but I tried some that didn't work. If anyone has some recommendations, feel free to share in the comments.