4GB is not enough for a developer who has several apps open in a 64bit Windows. I want to dedicate a whole 4GB to Visual Studio. I want to work in a screaming fast computer. You'll appreciate it when every task and click responds very fast and it's a joy to work.
Well,then like i said 8GB is the max i recommend for extremely-heavy usage.
About the link you posted,well its has a great price,no doubts about it,but it doesn't have any reviews, also its not as reputable as brands like Corsair,OCZ,Geil,G.Skill etc.
I know it's not known like the others. I don't want to be in a "you get what you pay for" situation and get memory which gets bad quickly. There are no reviews so I can't judge. It seems it's a new company/product and Amazon added it less than a month ago. The odd thing is that I can't find a site for Komputerbay. Which company is behind them?
As for 8GB or higher,I don't want to limit you,you can get any capacity you like,i just said that judging from the reviews i read,but its your choice
I did a search and it seems its a RAM which is mostly used in laptops, http://forums.macrumors.com/showthread.php?t=920420
"Great pricing for sure, although never heard of the brand. It looks like the actual memory chips are samsung, which is generally very good."