Windows Machine for comparable Macintosh

I really would like to get a Macintosh Desktop machine, since I've gotten a pismo with 10.4 I'm hooked.
I would be willing to trade my current workhorse desktop machine, an eMachines t3092. Specs are as follows-

AMD Athlon 3000+ 2.2ghz (2.17)
512mb RAM
CD/RW DVD/RW DVD R/RW,
CD ROM
It can read various memory cards
Windows XP SP/2

It is in good working condition. Depending on what anyone is willing to trade, I have also a Samsung SyncMaster 950p 19 inch monitor which is by far the best I have owned. Willing to negotiate shipping.

I would be willing to trade for any mac g4 over 1ghz.