Uh oh. I fear your questions are about to expose my ignorance. Tonight I'm too tired to care so let's get start!
Coding, Is there a more up to date page that discusses the duemilanove and the Uno?
I'm not aware of one. That's the link I use when folks have auto-reset problems.
How is the reset-en supposed to work?
That was discussed in the forum a few
weeks months ago. I think this was it...
If I understand correctly, the pads are there so a user can solder a bridge and restore auto-reset.
Doesn't look to me that it makes a difference whether it is open or not dueto having a trace in parallel with it, unless the cap is removed from the board.
The parallel trace is meant to be cut to (semi) permanently disable auto-reset.
I think a better choice would be to keep the cut-trace but include pads and holes so jumper pins could be installed.
Whew! I think I made it without too much embarrassment!