I haven't had a chance to ride on one of the 777s yet.
For coach, any of the 767s. With the 2-3-2 configuration, it's hard to get a bad seat. In a typical row, you get 2 window, 4 aisle, and only one middle.
For first, the 757. I don't know about other airlines, but Delta has 6 rows in first class on the 757s.
As for commuter planes, I like the Canadair Regional Jets. MUCH quieter than the turboprops.
I've always thought the 727 was a neat design with the three engines.