You can use jDownloader to fetch youtube videos :)

NB: growl notifications are not ready yet, see:
http://svn.jdownloader.org/issues/174

@razzo yes, it's 0.9581, aka 0.9.581:
http://jdownloader.net:8081/changes/index

Lates version is 0.8.821 not 0.9581 !!!

I recommend everyone to use nightly builds, it improves a lot this soft. Dock icon notification, perfect Growl support, menubar, unarchiver.
Look how to change version in it's forum.

Note -- When downloading their installer from http://jdownloader.org/download/index, be sure to turn off any ad-blocking tools. This seems to speed up the download.

Had to make that clear. :)

Great SpeedDownload REPLACEMENT.

However, when attempting to download turn off your ad-blockers, makes the download quicker! :)

Works great with all file sharing sites, premium or not; Also works fine on all my OSX systems as well as Windoze XP and 7 (64-bit).

После обновления программа перестала напоминать вин-продукт.
Понятный РУСифицированный интерфейс, работающий автоподхват ссылок.
Удобно! :)

i'd rather run something mac-native, but it's hard to argue with the results here. amazing time saver, if a little buggy at times.

Works brilliantly for me. Mediafire and Megaupload tested, with and without accounts.