It's a great deal.
(Un)lucky for me, my Xbox360 got a RRoD just a few days ago, so now I get the joy of staring at my game disc while I'm waiting for my lame-wad 360 to get unfucked. But, fortunately... I have had time to check out the bonus features. The LE comes with:
1. Hardcover Art Book - Too be honest, the quality (of the book, not the art) was a little disappointing; it's nothing that you can't find on this website. However, it's a great little ornament for your coffee table! And, if you haven't seen the content already, it is quite interesting.
2. Bonus DVD - Packed with content. A great value. Contains:
Trailer 1 (Reveal)
Trailer 2 (E3 2007)
Trailer 3 (Perks)
SP Walkthrough/Dev Commentary - "Crew Expendable"
Behind the Scenes - Research
BtS - Technology
BtS - Story
BtS - Multiplayer
Great SAS Missions (7-part miniseries detailing the SAS, each episode is about 20 minutes long. Great if you're into the History Channel, like me.)
3. CoD4 game - in a regular box.
The whole thing comes in a shiny cardboard box. Not quite as cool as a tin box, but still neat to show off.