I have a mid 2009 15'' 3.06 C2D MBP. I have the stock 4gb of ram and was thinking of upgrading to 8gb of ram. Under normal circumstance the 4gb does me well. However when I am surfing the internet, having youtube going, have Aperature open, working on a slide show...etc. the amount of free memory drops down to under 300MB. I was thinking 8gb would help out with this, and 8gb just sounds like a nice round number to me. The benefit of this is then I could take out the current 4gb and put those in my quad core iMac when I get it in a few weeks. However 8gb (2x4gb) are still fairly expensive and run ~$400-450. Then I came across this article on barefeats that basically shows no significant difference with 4gb or 8gb in a 3.06 MBP: http://www.barefeats.com/mbpp16.html. However I want to say that with having multiple apps open, the 8gb should make things run more smoothly. Any thoughts on this?