Best Resolution for YouTube

[fastdoom]

I will be uploading to YouTube and I need to know what resolution is the best. I see that low-quality videos buffer faster than high-quality videos.
I will be uploading videos in 16:9 (No HD) and I need to know the best resolution which has good quality and buffers fast at the same time.

[neelchauhan]

I guess between 640*360 or 852*480 would be the best.
Many people upload videos as HD but are really in 852*480 like the video at http://www.youtube.com/watch?v=A5EuYtyp_eA.
When I upload to YouTube, my videos are in 852*480 before I get a HD camcorder in end 2010-2012.