Anything good amongst the low-cost NAS boxes?

I've been seeing these things increasingly cheap lately, especially the single-bay ones in the 500gb range, so I'm considering picking one up. The ones I see most often are the Buffalo Linkstation Live, Western Digital Mybook and the Maxtor Shared Storage II, but reviews on the former two indicate painfully slow transfer speeds (<10MB/sec even on gigabit), and the latter is a Maxtor.

Are there any others in the sub-$200 price range I should be looking at? Or, failing that, what about enclosures that don't include the HDs?

Make one,

grab and old P2/3/4 or even Duron/Athlon system or even a via mini itx system with SATA card

install freenas, install drives, go!

I'd thought about that, and actually I used to have a fileserver running off an old PIII machine, but there are a couple drawbacks to that... Power consumption is the big one, but there's also the PCI bus bottleneck when using an older system, which could come into play when trying to use SATA drives and a gigabit ethernet connection.

Perhaps an ITX board would be a good option, but all the low-cost ones I've seen only have 10/100 ethernet, save for one Jetway C7 setup with dual gigabit. Even then it's $100, plus drives, PSU and case, so I was kind hoping to get out a bit cheaper than that if I could. Especially since I don't have a desperate need for such a thing anyhow. It's more of a "hey, that would be sweet if I could get one cheap enough" kinda thing.

I have heard a lot of good things about this one. If your needs are a bit more simple you may want to consider one of the WD units. NAS and HD in one, considering the price of the HD its not a bad deal.