I would go for the blackbook, it'll hold more ram (6 or 8 gigs, because it's one of the newest ones on the 965 chipset) and it's already at a faster speed, plus it's easier to upgrade the ram and hdd on them, and macbooks have a better keyboard than the old macbookpros.
The 2.0GHz Core1Duo macbook has a crappy keyboard, a slower system bus, a less-capable optical drive, will only hold/use a maximum of 3gb of ram (although they advertised it as being able to hold/use only 2,) and will be more difficult to upgrade the hard disk on. The only advantage that it may have is a larger display.
*Note about keyboards: This is a very subjective thing and I've heard of a lot of people who love the macbookpro and powerbook g4 keyboards. I, personally, think that they are the worst keyboards ever, and have specifically avoided buying many really good deals on brand new previous-gen MBPs because of how much I hate the keyboard.