Minor upgrade questions

Hey guys, i was cruising the Sunday paper today and found the Circuit City catalog in it. Inside it had memory, hard drives, and graphics cards on sale. I was wondering if they were any good.
Here they are:
Memory:
512MBPC2700/2100 SODIMM and,
512MB PC2-4200 DDR2 DIMM desktop (also avalible in 250GB)

In the hard drive catagory:
Western Digital 160GB 7200RPM SATA OR PATHA hard drive
or the SIMPLETECH external 160GB 7200RPM 2MB CACHE USB 2.0 hard drive. (also avalible in 250MB 7200RPM 8MB)

And in the Graphix card catagory:
EVGA e-GeForce FX5500 265MB DDR TV-out Graphics card.

They're all on sale for really cheap, so i was looking into getting them.

Before any minor upgrade run this little but very important programe called Belarc which can be found here.

http://www.belarc.com/free_download.html

This will tell you what type of motherboard you have and other intersting information you have.

They look like good upgrades to have.