Vixy is rubbish - the bit rates are crap and it's slow as shit...
This is a usefull link;
Code:
javascript:document.location='http://keepvid.com/?url='+escape(window.location);
Copy that and create a shortcut link in your links bar along the top of your IE/Safari/FF/whatever window
Then when ever you are on a youtube page and want to download the vid, just click that shortcut link and it'll automatically open the keepvid page with the correct download links already in place
