"Development" machine - a used Mac?

[Torfinn Ingolfsen]

Hi,

I bought the Mac mini with the intention that I would do FreeBSD
development (ok - testing, reporting bugs and so on, I'm not a
developer) on it. However, the mini soon took place as my home theater
machine, mainly because it runs MythFrontend well enough.
This means that it is "hard" to get it free for FreeBSD use, at any
given time.

So now I'm thinking about buying a second machine to mess around with
FreeBSD. I could just buy another mini, but I see that I can get used
G4's for about half the price of a mini here. And yes, budget is always
an issue. :-)
A couple of examples:
http://www.applehistory.norhost.net/g4agp.html
with 400 or 450 MHz cpu, 312MB or 640MB RAM
or
http://www.applehistory.norhost.net/g4_quick_2002.html
with 933 MHz cpu and 768 MHz cpu.

Would one of these be a good development machine?
And, does the G4 make a lot of noise, or is it (nearly) silent?
How much RAM do I need? Is 512MB enough, or should it have more?

Should I consider other machines instead?

Any hints welcome.
-- 
Regards
Torfinn Ingolfsen,
Norway