I really like how Apple implemented Lion Recovery. You can enter Lion Recovery by simply pressing ⌘R while OS X is starting up.
I used it this weekend to reinstall Lion on a MacBook Pro that I’m selling to a friend. (Yes, I went with the new 13” MacBook Air, and I’m loving it.)
In Recovery, I used Disk Utility to securely erase the Macintosh HD before installing a clean copy of Lion. The installation took about an hour, maybe less.
Best of all: I never had to look for a disk or touch an optical drive. Everything I needed was in Lion Recovery.