http://www.youtube.com/user/HDstarcraft (http://www.youtube.com/user/HDstarcraft)
http://www.youtube.com/user/HuskyStarcraft (http://www.youtube.com/user/HuskyStarcraft)
http://www.youtube.com/user/StarcraftScientist (http://www.youtube.com/user/StarcraftScientist)
Crota/Quota is pretty decent too, annoying speech impediment though
http://www.youtube.com/user/BlizShouter (http://www.youtube.com/user/BlizShouter)
edit: [url=http://www.sc2rc.com/]http://www.sc2rc.com/ (http://www.sc2rc.com/)[/url] is my favorite for actual replays, the replays of the week especially