How much faster than an 800Mhz G3 is an 800Mhz G4? I won't be using Photoshop. I guess I might do some audio and/or video stuff very occasionally, but I'll overwhelmingly be using it like a typical hard-working/busy college student for basic stuff. This doesn't mean speed doesn't matter to me though -- I'm very sensitive to things like latency of GUI and generally like my computers snappy. I'm aware OSX has some G4 optimization, but can't see how the effects could be that pervasive. Is the G3 actually faster on a lot of things? Give me ball-park figures like "G4 10% faster 75% of time, 5% slower 10% of time, and 80% faster 15% of the time." Any other things I should know while trying to decide whether to get iBook to replace in 2 years or TiBook to replace in 3 years?