I think I'll wait until the second generation of devices before making a decision. By then, we should have a good indication of the quality of apps being developed for WP7 and how quickly Microsoft will be releasing updates.
The problem is, once you buy into the Apple ecosystem (as I have), it's hard to get back out of it. Transferring all of my media to the Zune software would be a nightmare and I'd lose all of the apps that I've already bought. I'd probably have to buy a WP7 device and
an iPod touch.
However, if my employer wants to buy me a WP7 device, I'd gladly use it.