Hi guys I've had my 15" i7 2.66 MBP for 6 months now and love it to bits. I wanted the 8GB from birth, but with the price as they were at the time couldn't justify the extra £320 to do it. Now Crucial are showing it at £123. Much more wallet friendly and I can pass my 4GB down to the mrs for her unibody MB. I use my MBP every day at work and generally I end up with a lot of programs idling most of the day, but are needed regularly for short periods of time. Right now my activity monitor for memory is reading: Free: 200.4mb Wired: 666.5mb Active: 2.23gb inactive 818.9mb used: 3.68gb Does this mean I'm pretty much using up all of my RAM and the 8GB upgrade would be worth it?