here are 3 motherboards that i would recomend to anyone. they are stable, cheap and feature filled. (newegg.com prices listed)
Shuttle AK31A - $59
Shuttle AK35GT2 - $74
Shuttle AK35GTR - $76
the ak31a is based on via's kt266a chipset, has excellent onboard sound, and you can oc the hell out of it (i do at least ;p )
the ak35gt2 is essentially just an upgrade from the ak31, it uses the kt333 chipset, has the same great sound.
the ak35gtr is one step above the gt2 at it has onboard raid. only difference...and the price diff isnt that much either . BUT it still only has 2 ide channels...not 4 like you would expect.
from my experience the kt333 wasnt that much of a jump, comparitively speaking. the kt266 > kt266a was awesome...but if your running pc2100 ddr then go for the ak31a - its one of the most stable boards ive ever encountered and you can O/C from the bios (i've reached 152mhz fsb, 2 hours stable)
as far as a nic goes, smc's seem to work best w/ this board (pci slot 3). (a linksys card will work as well)
NOTE: ak31a isn't currently in stock @newegg , don't go for the ak32L , its a bad board in general...bad sound (sounds like a muffled blown 5watt speaker after being processed through a tin can), via kt266 (not a) chipset and doesn't O/C as well (147 fsb max)
when you buy an athlon 1600+ xp cpu and shuttle ak31a mobo you get 5 bucks off
anyway before i get off on a tangent thats my reccomendation, 59 for mobo 54.99 for cpu , throw in the cost of a shim , volcano9 (new and improved!!), nic, thermal paste and ram and your at 300 or so before shipping. ii'd check googlegear.com also , they have lower prices than newegg (sometimes) , always cheap shipping and great customer service.