Go for it. I purchased one and it arrived last Friday. Yesterday I replaced the hard drive with a 200gig 7400rpm and put 2gig of ram in it and boy does it fly. This made a huge difference. It's a great laptop and I wouldn't care if they came out with a new one tomorrow.
based on past revisions, updates typically come out in the fall and the spring. i don't think we'll see another update to the macbook line until april or may. while only a couple months away, i don't see what new revised macbooks would offer that would make me wait to purchase (unless multi-touch trackpads are really that big of a deal). if you can live without multi-touch, go for a purchase today.
If you need a new computer now then buy it is a great machine. If you don't then just wait for a new version sometime this summer ... MAYBE.
I know people don't like to buy technology then have something new come out but if you need it you get great value from the MB. So just buy it now, and use it.
Even if you don't anticipate using the superdrive, I'd get it. You may find a use for it and it'll increase resale value. Not much difference between the 2.2 and the 2.0 other than gaining the superdrive.
Get the middle 'white' model. Add your own 250gb (or 320) hard drive and your own 2 or 4gb of RAM if you need to.
I have a macbook I purchased in May. I just purchased another macbook yesterday because I was using up my 2GB ram and wanted the ability to have 4gb. I had a friend that needed a new notebook so I made her a deal and now we're both happy.