I recommend before installing Lion that even if you’re using Time Machine you also create a working clone of your Mac. This is because while you can restore data from Time Machine, it’s faster and simpler to do so from a clone.
He offers a couple of pieces of software — ignore all but SuperDuper!. Small backup drives are pretty cheap, even at places like Best Buy and Fry’s. I picked up a 1TB LaCie drive from Best Buy that is USB 3 for like $80. Not a steal, but a good brand and worth the peace of mind.
Oh, and if you want to upgrade to Lion when it comes out, then I suggest you get cloning tonight.
Ed. note: Many thanks to Stephen M. Hackett for helping with my comma addiction. It is a real disease.