New
#11
My suggestions for the boxes are as follows:
The C2D E7500 still has enough oomph (technical term for ZOOM ZOOM) to run Win7 or 8 if so desired. One might load it up with a Linux flavor as darn near everything in the box SHOULD be supported. I would keep it as a desktop wherever it ends up. Nice for give away.
The X3700+ with maxed RAM says 'Server' to me. The 85 to 90 W TDP makes me shudder especially as newer CPUs and APUs absolutely kill these old S939 chips. Too bad as a full time box but for long term storage that you shut off after a back up, maybe, YMMV.
The X2800+ is simply too little performance for too much power consumed(1.8GHz @ 89W TDP). I am sorry but the time for this over. The only thing I can think of for it at all is as a firewall but for that you would need two NICs.
BTW I have my full time server running on an Athlon II 255 (3.1 GHz @ 65W w 5 GB DDR2 and 4 1TB drives non RAID). I use a old X2 3600+ AM2 (1.9 GHz @ 65W TDP) for a once a week back up location. Slow and old but fast enough for my needs.