transcend's an ok brand.
corsair probably has the best rep as high-performance ram companies. crucial is considered high-quality ram also.
ocz, geil, patriot, and transcend are other companies who make high-performance (flashy) ram.
kingston and pny are mainstream ram and generally slower.
as for motherboards, it depends on your budget. if you're willing to spend another $100, you can probably get a core 2 duo CPU and a 965 based motherboard. but you'll have to wait a few more weeks and run the usual risks of being an early adopter of new technology.
if you're budget concious, but want to be able to possibly upgrade to a core 2 duo in the future, i'd recommend getting a mobo based on the 946g chipset. here's intel's model: http://www.intel.com/products/motherboard/d946gzis/index.htm
it has built-in graphics, sound, LAN, supports 4 SATA devices, 2 ATA(IDE) devices, 8 USB ports, and PCI Express slots (for high-performance graphics). It only 2 RAM slots, so I'd recommend filling them with 2GB.
if you just want a good, inexpensive PC now, then get a motherboard based on the 945g chipset. here are 2 suggestions:
biostar, $93: http://www.zipzoomfly.com/jsp/ProductDetail.jsp?ProductCode=246442
asus, $115: http://www.zipzoomfly.com/jsp/ProductDetail.jsp?ProductCode=247080