I'm very proud of my very first factory-ordered truck -- 2004 Silverado 2500HD 4x4 Crew Cab.  Looked long and hard at the options list and decided on the following:

LT package with addition of rear seat DVD (keeping the kids and wife happy on long trips), XM, locking rear diff, HD trailering equipment and 3.73 axle.  

Really debated the Duramax vs. the 8.1L and opted for the Big Block!  The 6.0L was not really an option for me...wanted the Allison tranny and heard MPG difference between that and 8.1L wasn't that large.

Dealer did t-bar crank and upgraded my tires to 285 BFG/AT-KO's, and installed nurf bars.  

I added Volant cold air intake and Westers PCM tune and swapped out all lubricants to synthetic.  Happy I'm getting ~11 MPG city and 12-14 MPG highway.

It's been a great truck!  I'm planning on keeping for a while since GM discontinued the 8.1L/Big Block in the HD line.