I already went but it looks like some of you need to learn about greasemonkey
https://addons.mozilla.org/en-US/firefox/ad...emonkey/?id=748
Also consider
https://addons.mozilla.org/en-US/firefox/addon/stylish/
http://userscripts.org/scripts/show/13333 or more generally
http://userscripts.org/tags/youtube (hint 2- many popular sites have scripts, IMDB having some especially good ones).
If nothing else you can lose the comments quite easily and then it becomes quite nice.
Similarly re copyright- at least in the UK (some of the Scandinavian/nordic and Asian countries are a bit harsh in my experience) you find a link that fails and you either search again for it, click on the little videos link at the top of most search engines and another version should appear if not on youtube then one of the many other video sites possibly even in better quality.
Failing that take the nice youtube identifier, build a full youtube URL from it and search for that entire URL- up should pop the name of the usually the song you want you can then search for.
Also noscript, ghostery and adblock plus if they were not already in your arsenal tend to trim down the ads, if you know a tiny bit about web coding or possibly even basic logic (HTML is very much a plain text "language") then firebug too.