recomended minimum requirements?

[Lotas Smartman]

right. i currently have a Revision D 333Mhz G3 imac. im looking at 
upgrading. im planning on putting a G4 upgrade card into it, making it 
run @ 466Mhz. im also planning extra memory (currently has 288mb, want 
it to have 512). its just gotten a new hard drive (80gb) and also aim 
planning a move too. putting it in an ATX case and getting a different 
monitor, probably a 17". anyway, would these requirements be ok for 
software of this day and age? i know the 333G3 is from 1999 or so, and 
im guessing the G4 is from about the same time. this is quite old 
hardware, and i want to know that im not buying a lemon as such. i know 
the G4 is a fast chip, and its still being used a lot, but it is only 
running at 1/3 the speed of the fasest G4. like any pcs i have that are 
that slow have become routers/headless linux boxen/compile farm 
helpers. i know the mac is a lot nicer to old hardware then Microsoft 
are, but are they that nice?
Thanks in advance.
Lotas T Smartman, MCP
www.lotas-smartman.net
www.the-hairy-one.com
www.lsn-blog.tk