One other thing...
You didn't mention what you were using initially. If you already had 2gb of ram, it's unlikely you'd notice any difference at all unless you're running memory intensive applications like CAD or Photoshop.
It's arguable that you wouldn't see much of a difference from 1gb of ram if you're running a nice, clean OS.
If you upgraded from 256mb or 512mb, you'd notice a blazing difference everywhere.
