Hi Ike,
Santa Rosa will be some new kit that includes some extra/better features & abilities, such as whats already been noted. Its going to be a good improvement. But there are always improvements "around the corner", and I dont think its worth waiting for. Although it'll be great, it'll be no greater than all the other great next-big-things, and 6 months after santa rosa there'll be another brilliant innovation ready.
Of course, this is a little bit hypocritical...I've held off from buying a new Macbook Pro waiting for the new version, but only for a month or so. Especially if you really want a computer now, its not worth waiting half a year.
Look at it this way, although the santa rosa thing will be really good, it probably won't be great as the fun you'll get from using your new computer for the next 6 months 🙂
Aaron