Absolutely my favourite mac of all time, and my saddest tale, I owned this mac for a glorious couple of years before it was damaged in a fire to be replaced by a mac mini.
It wasn't all that fast, the G4 processor made much better use of the 700mhz available to previous G3 models but nothing to write home about any more. This means OS tiger is really the only option so no new software.
With 256MB RAM this machine can easily handle Music, Video, web surfing and emails. All the things apple want to make accessible.
What really makes this model is the enclosure, its just absolutely beautifully designed and executed. The semi-spherical body houses a quiet machine, power suppy, DVD Reader, CD Re-writer, two USB ports, Two Firewire ports headphone and speaker outputs.
The 15" Screen is a flat panel enclose in transparent perspex and supported by the most genius engineering. Apparently this thing holds many patents all to itself, the self tightening joints mean it never comes loose and always have support to hold the screen at any angle you choose. For transportation, the arm is strong enough to use as a handle meaning this machine can easily be moved around completely in one trip.
The included speakers are very clear for their size and do not need upgrading like many other PC speaker packages.
Its not fast, its not even that capable these days, it's just jaw droppingly beautiful.