Oldest or newest...? I have a mismash, I'm posting this from a refurbed Mac Cube:
PPC G4 1 GHz
1.25 GB RAM
120 GB ATA HD
nVidia GeForce3 graphcis w/64 MB VRAM (no, I do not play WoW on this thing ;-))
Apple Studio Display 15" viewable 1024 x 768 res
DVD/CD ROM
It does what I need...