Just dropped my 2002 D/A off and drove my new 2006 3500 SRW home.
A couple of quick observations:
2006 rides much nicer which is surprizing when comparing a 2500/3500.
2006 handles more car like
2006 much quieter.
2006 quicker
2006 head and fog lights improved
2006 mirrors are awesome, better the TTT and Ford
Loved my 2002, but proof even great trucks can get better!

Congrats on the new truck!!! A few weeks ago I bought my 05 2500HD and now I regret buying the 05. I should have bought an 06 instead. Friend of mine picked up his 06 last week and his truck cruises at about 1850 rpm's at 70 mph. When I cruise at 1850 rpm's I am only going 59 or 60mph.
That 6-speed tranny is going to be a fuel savor on the highway.