If I had to answer that in a word, it would be... groceries. I like groceries, I like having them in my house. For various reasons; they taste good, they fill me up, they keep me healthy.
All in all, I think my enthusiasm for maintaining a smallish selection of foodstuffs in my home is probably at the core of why I'm still using an 800 mhz QuickSilver.
You can't think of another use? How's this: I use my old mac for Photoshop, Flash, After Effects, a bit of Final Cut Pro. I also play music on iTunes and surf the net a bit. A friend of mine does a lot of audio recording on his G4, but I guess his is a 867, so it doesn't qualify as "old" does it?
So true. I find it comical when I hear people say that older machines don't have any life left in them.
Look at my sig for example.... Nothing, aside from my newly ordered MBP (which I ordered last night, due in on the 25th!), every machine in my possession is over 4 years old. My iMac G4, currently my main computer, sees professional photography work (in Photoshop Lightroom), Final Cut video editing for my Film Class, and heavy graphics work in illustrator. Additionally, I do recordings from time to time of live music, and it does all these tasks in a manner in which I'm still highly productive.
Now, my 400MHz TiBook is really a web-email-word processor unit due to its slow processor speed and minimal RAM (384MB),
and with its pooped screen and fussy keyboard, it will be retired once my MacBook Pro comes in. Nontheless, in the past two years I've owned it, I've used that computer on a daily basis for my on-the-go needs. It's also signed by Steve Woz... Pretty awesome artifact of Apple History.
My G4 Tower, displaying on a lovely 17" Apple Studio, is my parents main computer, and they use it for everything that any mid 50s baby boomers would use a computer for: they have no complaints. 466MHz is still uber capable, provided you know what you're doing: run the right OS (Panther), and have the RAM.
Anyway, my point is, old computers are still useful, especially older Macs. I sincerely have no complains with my current system as a whole, and my only complaints are in the fact that until now, I didn't have a useful on-the-go machine. With my 15" MBP (2GB RAM, 160GB HD, iWork '08, Non-glossy screen) due in next week, I will defiantly be happy, but at the same time a bit sad. This will be my first Mac that will not run Classic or OS 9... Kinda a big step for someone who has been a Mac person since 1994; someone who moaned and thought the world was ending when the PPC to Intel transition was announced. Oh, oh, the irony!