Hardware to buy with NSF grant

I am going to put a range of computers on the LAN in my office for SAGE developers. Please put suggestions here about possible computers to buy:

Possibilities

Definite

Notes

For PARI, from Bill A.
I think at this point what we really lack is ppc64 hardware, e.g. a G5
running in 64bit mode. Having buildlog for ppc64 would be nice, see
<http://pari.math.u-bordeaux.fr/buildlog.html> for what we currently
have.
 
Having access to a Core 2 Mac could be also useful.
 
I also have so plan to add level0 assembly kernel for ARM processors
(at least for those which support 32x32->64bit multiply). I don't
know if people are actually running PARI/GP on their PDA.