1. JosefVStalin has got up over 1200 videos. Doing SC 2 right now, but commented videos on a wide variety of strategy games are available. He is an excellent and informative commentator. Has a commentary on Rise of Nations in there somewhere.
2. HDStarcraft and HuskyStarcraft are both excellent commentators on SC2 match play. These guys really know SC2 and can hold your interest even if you don't like SC2! They are cult leaders!
3. GetDaved is the only one I have found who has done a Sins of a Solar Empire play through. Lots of other games. A very competent player.
4. SsohPKC great commentary with a bit of wry humor. Wide variety of games. Check out his commentaries on Borderlands, because even if you hate fps you will find yourself waiting to see what will happen next. The Hitler Stache and as many as you want.
5. MajorSlackVideos great commentator with good sense of humor.
6. TheMelnTeam has a lot of great Civ 4 videos, plus other. Will probably be on Civ 5 when it releases.
7. bonecanoe86 good play through of Civ 3 and has done some Sims 2 also I think.
GetDaved is the only one I have found who has a Sins play through. This is surprising since Sins really has great graphics and plenty of action. Sadly, GetDaved stayed zoomed out the entire time pretty much and just concentrated on the strategy level. A very unique approach too!