A couple of questions regarding the basic iMac models. I am a basic user (browsing, email, etc). I also like to keep them for a long time. I am currently on a 2008. Can someone help me answer a couple of questions? 1) What is the biggest difference between the 1.4 and the 2.7Ghz? I am sure speed is the obvious answer. The other difference is 500 GB hard drive vs 1TB. Are these upgrades worth $200 for a user like me? 2) Should I buy an apple refurb or get one from Bestbuy? Is there are real difference? Are the Best buy models older? I only say this because I do keep them for a while and would probably benefit from buying the latest model? Thanks for any suggestions.