I ended up selling $250 worth of old computer junk on ebay, and got some cash for the holidays, so I ordered:
e8400
Biostar I45
ASUS HD4850
OCZ StealthXStream OCZ600SXS 600W
Sunbeam CR-CCTF 120mm "Core Contact Freezer" CPU Cooler
Arctic Silver 5 Thermal Compound
50' HDMI and 50' coax SPDIF (figured I'd have to use this for watching HD movies/possibly gaming???!!! on the CRT RPTV)
This will all be stuffed into the Raidmax Smilodon case, and go with the OCZ 4GB DDR2 1066 memory I bought last month. Thanks for your insight -- I didn't go anywhere close to my original $300 plan, but I did learn a good bit from everything else.