building a pc

Hi
This is my first time building a computer and I am not sure what are the good but afforadable products out there. Any suggestion?

currently I have:
case
graphic card
hard drive
flopy drive
power supply
memory card
CD RW
keyboard

stuff I know that I need to buy (am I missing anything?):
motherboard
chip
heat sink
mouse
monitor
speaker

Are there any specific type that I need to buy?
Thanks in advance for any help/input