Lion and BootCamp - better safe than sorry
If your Bootcamp partition crashes, you cannot simply put in your Windows DVD and reformat it. You will need the DVD or dowloaded install image of Mac OS X. Have learned -- the hard way -- a few safeguards, just in case something happens to the Windows partition running Bootcamp:
1. Get a decent-sized USB drive (8 gigabytes or more) and regularly run the Backup and Restore control panel in Windows 7 (or Vista).
2. Manually back up any other important files on your Bootcamp partition (better yet, keep them on your Mac partition). But you'll use those after all the fun you have reinstalling the Bootcamp partition and reinstalling Windows.
3. Keep these items on hand, in a place you'll remember:
A. The latest Mac install DVD (This computer came with Leopard, but I purchased an upgrade to Snow Leopard) used with your machine. Last I checked, I could NOT download the Bootcamp utility separately from the OSX install DVD or disk image.
B. Your Windows 7 (or Vista or XP) DVD and any other applications you run on Windows.
C. The Install Key number for Windows
D. The Install Key number for any other Windows application and if it is an upgrade version, the previous version Install Key numbers as well (especially Adobe stuff)
You will need all of these in case of a crash. And if you need tech support to reinstall the Bootcamp partition, plan on dealing with Apple, not Microsoft

In my case, my Applecare paid for itself in just one incident. You probably WILL need to contact Microsoft's serial number activation phone numbers after a crash -- because you won't have time to deactivate those numbers and Windows may think you're running on an unauthorized copy.