http://www.twitch.tv/barnyyy
This guy isn't a pro, but he's probably high(ish) level. He seems to have a better than adequate understanding of Dota.

This guy comments on his game play A TON. He's kinda funny, and it's an entertaining stream to watch. Best one I've seen in a while. I suggest you check it out.

I have never watched a lot of streams for any game, I really need to start. I'll keep an eye on this guys channel.

www.joindota.com - Pro matches and commentary

http://www.youtube.com/user/PurgeGamers/featured - Purge makes some pretty good instructional videos to get you started

Once you pick out a few players that you like in pro matches you can search their name in the DOTA 2 client and watch the game from their perspective, which is also helpful. Na'Vi Dendi is one of the best out there right now.

Neither did I, until I started playing a ton of Starcraft. Now I pretty much watch any high level stream of any game I'm trying to learn/get better with. Not only is there a lot to learn - but there is the entertainment factor as well.

http://www.twitch.tv/sing_sing /thread (Warning: Sing has some colorful language)

Yeah i love watching sing sing!

"I love spider pussy"

Side note Alv, would it be possible to have a stream/tournament viewing channel in the mumble? Often times people will be watching a stream of some tournament and there really isn't a place for us that isn't invading another channel

Yep, I'll add it now.