Advice for an old P4 build

[a6]

I presently have this hardware available.
It might not the most efficient box, but it's freely available.

• Intel Pentium 4 640 3.2Ghz
  Intel D915GUX http://www.motherboards.org/mobot/motherboards_d/Intel/D915GUX/
  4GB PC2-6400 DDR2 400Mhz
  ASUS EN8400
  Seagate ST3160023AS

The PCI x1 slot is blocked by the PSU leaving me with the option of a PCI NIC or using the PCI x16 slot for the NIC therefor utilizing the on-board Intel 900.

I'm looking for recommendations on a NIC and HDD.

Also looking to lower heat by getting a CF-Adapter if anyone thinks it's worth it. If so what options seem to be the most compatible/reliable?

For under $30 I can get a PCI PWLA8492MT. For more or less the same price I can get a PCI-E EXPI9402PTBLK.