You just put this in your bookmarks as the URL, then you go to the page of the video you want and click the bookmark. It will take you right to the download page with a plethora of quality options.
javascript:function inbtwn(a,b,c){ try{ var a1 = a.split(b); var a2 = a1[1].split(c); return a2[0]; }catch(err){return '';} } function inbtwn2(a,b,c){ try{ var a1 = a.split(b); var a2 = a1[2].split(c); return a2[0]; }catch(err){return '';} } var src = document.body.innerHTML.toString(); if(window.location.toString().toLowerCase().match('youtube.com/')){ var v = inbtwn(src, 'video_id=', '&');var t = inbtwn(src, '&t=', '&');var fl = inbtwn(src, '&fmt_list=', '&');var title = inbtwn2(src, 'title=%22', '%22');if(title == ''){ title = inbtwn(src, '%3Ch1 id=%22vt%22%3E', '%3C'); };if(v != '' && t != ''){document.location='http://www.keepvid.com/?url=http://www.youtube.com/watch%3Fv%3D'+v+'&vid='+v+'&tid='+t+'&flid='+fl+'&titleid='+title;}else{document.location='http://www.keepvid.com/?url='+escape(window.location);}}else{ document.location='http://www.keepvid.com/?url='+escape(window.location); }
It's really helpful, so I thought I'd share.