Best converting app for full screen videos?

[lu0s3r322]

I have a couple movies that are in .avi format and I want to convert them to .mp4 files that are high quality and look great in full screen. I tried iSquint, which converts files for iPods and TVs and the TV one wasn't so great. So are there any good, easy to use, good-looking apps?

 

[Queso]

Lots of people use and swear by ffmpegx

 

[Eraserhead]

Lots of people use and swear by ffmpegx

I'd recommend the same, though the website is now http://www.ffmpegx.com