Well, If you like 3 year old technology, cheap parts, an OS that the machine barely meets the minimum specs for, don't mind that it's almost completely non-up-gradable, and don't mind paying more than it would cost to build a new one (and yes, that includes Vista Home or XP), and you're OK with refurbs, then by all means buy this bad boy.
It's just a bad deal, and for some reason, people just eat this stuff up on woot!. You do realize that the reason stuff ends up on woot! is that no one else wants this junk? Occasionally you can find a worthy deal, but trust me, this ain't one of those times.
Someone asked for proof that it could be built new for less? Someone posted a list on page 1 or 2 already. I'd do it, but I'm not in the mood to do the legwork for you.
Heck, for about $500-600 at newegg, you could build a machine with new, good parts, including a dualcore (slower speed, yet it would destroy this pentium in every perf. test), an 8600GTS, 2gb of ram, 320gb HDD, and Vista Home.