The software I use to download you tube files is ashampoo clip finder.
It also searches metacafe, google video, yahoo video, ifilm, and lot others
Only problem is that you can only search and won't be able to browse like top rated, most viewed etc generally. but you can sort your search result according to the relevance, rating and views
Link to clipfinder:
www2.ashampoo.com/webcache/html/1/product_2_0055__.htm