Help with Memory device...

Hi guys,
Im probably going to San Diego Ca. tomorow, and I would like to take this oportunity to get some memory for my PC, but Im not shure what to get...
I was hopingthat may be, by looking at this picture, you could help me pick a 'memory' from the site I link below.
*I would like to know if I can use the ones in the 2nd and 3rd link.
Thank you guys.
http://img70.exs.cx/img70/3783/ram2ic.jpg

http://shop3.outpost.com/template/harddrives/

http://shop3.outpost.com/product/3328752
http://shop3.outpost.com/product/362...20Memory:Spot2

My system spects are:

Intel Celeron 2.5GHz
128mb RAM
80GB HardDrive.
Windows Xp
etc.
what else do you need to know?

btw, Im after 512mb.

Nope need your mobo & cpu specs.

Get the Mushkin.
Lifetime warrantee as opposed to that other brand's one year.
The PC3200 is faster than your current stick, but it will default down to a speed your board can support.

I already bougt it,
it's 512mb, but don't remember the brand,
I just went to 'that' store this wednesday and showed my actual 128mb memory to one of the guys and asked for the 512 one!,
later at night when I put it in and '!wow!, now I can almost do anything, like download use internet and play music at the same time...
...this freedom is beautiful. Now I have 640mb RAM.
Should I go for 1Gb?