Games are too long to watch a full Let's Play for the most part. I prefer people making a video where they either play a new game for about 10 minutes or a retrospective type thing. Both are shorter and cuts to the funny stuff instead of the boring middle of things.

The only two Let's Play that I have liked are

1) The play throughs of the the Space Quest game because the guy voiced all the dialog making it a bit of a new experience.

2) The Spoony Experiment's Let's Play of Swat 4 because each video was pretty short and it wasn't completely half-assed.