I'm certainly looking forward to trying out Aperture. It seems like an amazing tool for anyone seriously interested in digital photography. The nondestructive editing and versioning is amazing, and if it's half as usable as it seems from the demos it'll be a great product.

As to the specs, as Loren says, as long as you aren't working with 10+ megapixel raw files, you probably won't need all that horsepower. While microsoft claims XP runs on a 233mhz PII with 64MB of Ram, they're in the bussiness of selling software. Apple, on the other hand is in the bussiness of selling hardware - Aperture is most likely a loss leader mainly put out to get people to buy power macs.

Matthew