check out barefeats, they have all the information on the differences of the video cards & chip configs from this MBP to the last...
http://www.barefeats.com/mbpp06.html
Insights:
The "late 2008" 15" 2.8GHz MacBook Pro is incrementally faster than previous MacBook Pros in terms of CPU intensive actions.
The "late 2008" 15" 2.8GHz MacBook Pro* is about 20% faster than its fastest predecessor (2.6GHz MBP) when it comes to 3D graphics benchmarks.
(*Some of you have asked about whether the 2.8GHz is worth the extra $300 or 12% more than the 2.53GHz model. If you go by the core clock speed, which is 11% faster, the price difference seems appropriate. So you have to ask yourself, "Is it worth paying 12% more for 11% more speed on CPU intensive apps?" "What do I have more of, time or money?" And, "Will I eventually recover some of the extra expense in terms of higher resale value when I eventually sell it?")