Mac Mini and ibook

Okay, so I've had my G3 ibook hooked up to a monitor and maxed out with usb and firewire entities. I decided to buy a Mac Mini 1.4 and an airport card, so I could use the ibook as a laptop. Needless to say, the Mac Mini is fast and awesome, but I find myself using the ibook more--since I can bring it to the couch. All that aside, there is one problem: I find myself wanting a better laptop; my ibook is great, but it has about 3.7 gigs left in the hard drive, and it is slow when loading the OS and other programs. The ibook surfs the internet nicely, so I really should ride it out; afterall, it was my first tech changing Mac.