Wow, I just upgraded my macbook pro from a 2.16Ghz to a 2.8 Ghz and am very impressed by the increase in power.
1) Ableton Live CPU Meter % : 49%
2) Laptop/Desktop? Make/Model? Macbook Pro
3) Operating System? OSX 10.5.8
4) Ableton Live version? 8.0.5
5) CPU Make, Model, and Speed? 2.8 GHZ C2D
6) Amount of Ram? 4gb
7) Soundcard (and driver version if you know it)? Internal

Hard Disk Drive Speed (if you know)? 5,400 rpm
9) Number of playback tracks? 8
My performace
test with my previous machine was some in the high 60's, almost 70% on this
test, but here's the interesting thing: On my 2.16 Ghz macbook pro, when I duplicated the tracks in this
test, I could comfortably play 10 tracks without glitches. The 11th one would glitch slightly and then play smooth. On my new 2.8 Ghz macbook pro, I can comfortably run 16 of the tracks in this
test without glitch. The 17th one has an initial glitch and plays smooth. And I'm not even running coolbook anymore, which really helped before squeeze and extra track or two out. Quite a nice improvement!
Professional Shark Jumper.