a good sound card is the "Sound Blaster Live" and an excellent sound card is the "Sound Blaster Audigy 2 Platinum" but onboard sound with the MB can be almost as good.
Get a Sony CD burner and a Pioneer DVD drive/burner
PC100 is REALLY SLOW compared to PC2700 but PC3200 is even faster than PC2700
Floppy drive: doesn't really matter as long as it works
Get a Radeon 9600 Pro (for better cost vs performance)
Hard Drive: I like the Seagate drives. they're really quiet, relatively inexpensive - not cheap-parts-sort-of-thing - and are good quality
Cooling: depends on CPU but the Thermaltake Volcano is really good
also get whole system cooling, the Thermaltake CFAN-SM8 (can be seen here:
http://www.scorptec.com.au/index.php?prdid=00003129) <- this site is in Aussie dollars
Monitor: get a Sony Trinitron, ive seen a 21" for just $399 (Aus) at a swap meet.
Motherboard: Asus P4C800 Deluxe Gold, you can find the specs here:
http://www.scorptec.com.au/index.php?prdid=00006199 (again, Aussie dollars)
it has onboard LAN 1000 Megabytes per second
supports all AGP graphics cards
and all DDR RAM disks
Has a feature called "Crashfree BIOS2" <--this doesn't mean that your computer crashes for free... lol
It is easier to reset the BIOS