After playing with OS X and the SSD, the bottom line for me, that for $449 is not worth it.
It's fast, really snappy and all, but price is the only factor. I can't really wait until prices come down. If the 160GB was around $150 now, I'd say everyone upgrade to one.
For $400, it's an expensive price to have the latest tech. If you can afford it, do it, though.