If the objective is running Crysis he should be putting his money towards a gpu and any other parts needed to accommodate it first. Ideally the upgrades I suggested would be best purchased in stages, something I forgot to mention before. The first thing to buy would be the gpu (either a GTS 250 or GTX 260) plus the Antec 300 and psu combo deal. Should he still have problems running Crysis the next step which would be buying the p43 and a cpu cooler to overclock the e1400.
You said the Celeron could bottleneck any modern gpu, based of my experience with a very similar chip I said I thought that a GTS 250 level card should be fine. I never said either the e1400 or e2180 at stock would beat a 7850 or 7750, I even agreed that the 7850 was the better cpu.
AM3 support isn't a advantage until AMD releases cpu's noticeably faster than the top end 775 chips.