The original uni mb screens in late 08 left a lot to be desired, especially the 9c89 model: poor contrast, lousy display differentiation of darker hues and an extremely narrow viewing angle. The 9c8c weren't quite as bad, and I fine mine to be acceptable.
Apple, like North Korea, never admits that it made a mistake (except for the mobile me rollout fiasco). In the early part of 2009, Apple did a stealth update to its unibody macbooks and started using better screens until they quit making them in June. Especially compared with the originals, feedback on the newer ones have been positive. Where they stand in comparison to the new 13" mbp's, I'm not sure.
Either choice can be a valid option, and both should easily do what you're wanting to accomplish. IMO, it's a crapshoot about what screen you'll get. But, if you get the macbook and the screen sucks, get on the phone with applecare (don't mention anything about mac forums or the screen model number) and tell them you're sending it back because the screen is unacceptable. (I managed to get a 9c89 swapped with no restocking fee by showing the genius at my apple store an apple video of the october 2008 focus on laptops event, and even he had to admit the contrast was terrible).
OTOH, getting a new mbp is more of a sure bet if you're able and willing to pay a couple of hundred dollars more. You'll also get the new battery, sd card slot, and firewire (in case you'll ever want to use it).
Another option is to get a used uni mb off of craigslist, all of which should be covered under original applecare warranty until october of this year at the earliest. Ive seen people selling the base model 2 ghz 09 models for $900, and it includes no sales tax. If you go this route, make sure you get a copy of the receipt, and bone up on how to verify what the screen's model number is. Taking a black and white or film noir movie on dvd with you to inspect the contrast is a good idea, too. Make sure you meet them in a public place (no shipping with CL!) and spend some time with the computer before you buy it.