Considering upgrading to MacBook C2D?

Macworld review says - Macworld: Review: MacBook Core 2 Duo/1.83GHz and 2.0GHz: "Improvements of that magnitude probably won’t turn you green with envy if you’ve just invested in a Core Duo MacBook. But if you have an older Mac laptop, consider this: the Core 2 Duo MacBooks are 55 to 65 percent faster than the fastest iBook—and 27 to 35 percent faster than the last PowerBook G4—on Macworld’s Speedmark benchmark suite. (According to Apple, the new MacBooks are actually six times faster than the last iBooks on some benchmarks.)"