Apologies if this has been covered elsewhere...if so just let me know I am considering the base 15" 2.4GHz MBP but am unsure about upgrading the drive to 500GB. I want more than 320GB of capacity however I am wondering if I am better of upgrading the drive myself later? Ideally I would like a 1TB drive in there...has anyone done this? I know it is easy enough to change the drive so this is probably my best bet right??