The iMac Core Duo, the Mini Intel and the MacBook Pros all use the same RAM.
According to the Apple Store, the 1 x 1 Gb is standard, but you can drop the price by $100 by choosing 2 x 512. 'Course, then you're kinda pooched for upgrading, but there you go.
I predict a rash of sellers advertising "MacBook Pro 17" $100 off Apple's Price!!!" and then supplying the 2 x 512 configuration. Bah.