A more comprehensive and easier to compare list of arduino and arduino clone boards:
http://www.duinoaday.co.uk/hardware.html
I looked at the list and and I didn't see the Seeeduino Mega or Seeeduino V328 in there.
I'm not sure if I want one of them or the Duemilanove. I'm not sure what I can do with the difference in memory.
I'm not really sure what the Arduino is and the comparison sheets just look like a bunch of ingredients for someone who doesn't know a lot about cooking. I'm not really sure if I wouldn't be happier with an Xmos board.
Thanks to all that responded though.