30 Boxes works fairly well on the N800. However, GCal might, or might not show everything. Most of the calenders that I have setup in GCal don't even display.
As everyone else has said in other posts, Google Docs and Sheets do not work, but this is an issue for Google and Opera to work out.
I look at digg several times a day with my N800, but you will need to scroll sideways if you want to see those frames.
I'll look into the others.