I just picked up a N810 yesterday and found that youtube ran very poorly in the web browser. It occurred to me to try the XL version of youtube that was linked to in my Nintendo Wii's Opera-based browser. Works very nicely on the N810, especially with the dark Diablo theme. Check it out if you haven't already.

Sorry if this has already been discussed... I'm a newb but know enough to search first and didn't find anything.

youtube.com/xl