I'd use Bitlocker for your Windows 7 laptop, as a previous commenter noted it has a mode to work via a USB key inserted at boot time. In my experience it's been fast and unobtrusive. I've never used TrueCrypt, though I've looked into it several times and remembered thinking that it looked just as good (or better) technically as Bitlocker, but the UI is really horrid and overly complicated if you're looking for something that's a "no-brainer": http://www.truecrypt.org/screenshots

Bitlocker Tips:

1. You might have to enable it in your group policy (see http://www.sevenforums.com/tutorials/4681-bitlocker-drive-en...) for the option to use a USB key to show up.

2. You'll need the USB key inserted to power on the laptop or resume from hibernate, but not for waking it from sleep. That helps with convenience since you won't have to use the key to unlock it from sleep.

3. Make sure to back up the Bitlocker Recovery Key saved to the USB drive. It's saved as a hidden file, just put it somewhere safe online in case you lose the USB key.

4. Don't lose the USB key along with your laptop! Since that sort of defeats the point of encrypting the drive in the first place...