I've had Apple systems for over 10 years now, all received second-hand. I've broken each one down, rebuilt them, and upgraded them with some of the better components I could find.
From playing Diablo on a ancient 66MHz PowerPC 7100 system under OS 8.1 to playing World of Warcraft or Halo on a heavily upgraded G4 system under OS 10.5.4 and then a Hackintosh running 10.6.3, I've tried to get the most use out of my Macintosh systems.
Primary Mac:
Hackintosh!
Intel E5200 @ 3.75 GHz
Secondary Mac:
Power Mac G4, "Digital Audio"
Mac OS X 10.4.11
OWC Mercury Extreme PowerPC 7455B @ 1.33 GHz (underclocked), 256 KB L2, 2048 KB L3, 1.60v
1.5 Gigs RAM, SDR PC133, Samsung
ATI Radeon 9700 Pro @ AGP 4x, 128 Megs DDR
40 Gig Seagate Barracuda IV HDD @ 7200 RPM
20X Dual Layer DVD-Burner
10/100/1000 Ethernet
802.11b/g AirPort Extreme
Misc:
Five USB 2.0 Ports
Two FireWire 400 Ports
v.90 Modem
Bluetooth 2.0 EDR
Other systems I own:
Power Mac G4 "Digital Audio" 533 MHz
Power Mac G4 "Sawtooth" 400 MHz
Power Mac G3, 400 MHz
Power Mac G3, 350 MHz
Two Beige Power Mac G3s, overclocked to ~373(?) MHz
Blue iMac G3, 333 MHz
PowerPC 7100/66AV