The only benefit to the elite system is hdmi cable ($10 value?) and 120 gig HD
The pro has an HDMI port and 20 gig HD.
The holiday bundles are $350 and $450 respectively and come with hdmi ports, Marvel Ultimate Alliance and Forza 2 Motorsports.
I found this deal last week:
$399.99 XBOX 360 Bundle
Pro HDMI Game Console
Orange Box
Bioshock
Two Worlds (traded it in for Halo3)
Forza 2
Marvel Ultimate Alliance