Drag and drop from youtube. Someone tried this yesterday and was very disappointed that it wouldn't work.

He kept trying to drag the file and couldn't figure out why. Eventually, I had to explain to him that itunes doesn't support that. You could also have a bin or allow dragging to the toolbar. An 'alternate flash downloader' would be a nice option. So it holds and offers to let you save flash files (including ad's) instead of displaying them. Especially good for weaker machines... add that to a job system to convert them in the background and you've just done something damn useful for users of older PC's. Especially users of older PC's with a portable video player.

Also, select output by player model is a nice touch. You can let users try out the files and figure out what works, then add it to the list of supported models. Probably isn't done very often for legal reasons. See the case with 'compatible with _____ razors' for the legal standing of why you might be able to list the mp3 players and consult a lawyer. I believe it was a case vs. Gilette... I can look it up... for a copy that supports batch conversion and youtube downloading. ;D