I suggest you to look at these links:

http://www.specs.de/~danni/avr/compars.htm
(hi Peter :P)

Regarding Steve's comment

[Steve M. Taylor wrote:
-------------------------------
AVR=ATmel=unreliable hardware with undocumented bugs, promises of revisions that never happen.]

have a look at this thread:

http://www.avr-forum.com/dcforum/AVRForum/718.html

Regards,
Enrique.