^+1 to davisflow.
In fact, since you do not need a case, that brings the price down. Also, the 5670 has dropped in price. Look at this SAPPHIRE 100287VGAL for $67
A little checking reveals the memory, the hard drive, and this DVD burner
are all $3 less, although the PSI is $2 more.
So the total on this build with your circumstances to $336. Close enough? I just built somthing similar, and it does the job.