I've just acquired a MacPro1,1 with the following specs and I'd like to install a later version of Mac OS X onto it. I know this would involve using EFI64 emulation software and possibly even replacing my video card, but I still think it would be worth it to look into.
2x Xeon 5150 2.66GHz
nVidia GeForce 7300GT 256MB
ATi Radeon X1900 XT 512MB
160GB, 120GB, 2x 200GB Hard disks
Mac OS X 10.7.5 Lion
I would like to run Mountain Lion or Yosemite, but if I need to use a later version I can do that.
If it matters, it has a dual layer capable DVD drive.