In order to save the twenty bucks, you have to purchase either ALL games or ALL accessories.
As long as you plan on maxing out your controller stash on day one, or buying a couple of launch day stinkers, you'll be fine.
The following games will be out on launch day:    4X4 EVO 2    AirForce Delta Storm    Cel Damage    Dark Summit    Dead or Alive 3    Fuzion Frenzy    Halo    Mad Dash Racing    Madden NFL 2002    NASCAR Heat 2002    NASCAR Thunder 2002    NFL Fever 2002    NHL Hitz 20-02    Oddworld: Munch's Oddysee    Project Gotham Racing    Shrek    Test Drive Off Road - Wide Open    Tony Hawk's Pro Skater 2x     TransWorld Surf  Halo's about the most impressive.
Tony Hawk is probably good as well.
I've heard disappointing things about Oddworld.
I played Cel Damage: imagine Twisted Metal mixed with Whacky Races.
Dark Summit will be eclipsed by SSX Tricky, when it comes out.
I don't play sports games and I won't touch anything with the word "Shrek" on it.
Not sure about the rest.

XBOX - read the not so fine print
