I've been trying to convince myself I can wait another year to upgrade my mid-2007 2.8GHz iMac, but things seem awfully slow lately and I'm tired of seeing beachballs while things page out due to my lowly 4GB of RAM. I'm trying to decide between the dual-core 2.5 or dual-core 2.7. I suspect the 2.5 will be fine, but my first question is, have any of you bought the 2.5 and wished you had bought the 2.7? If so, why? Likewise, has anyone bought the 2.7 and realized they maybe should have saved $100 and the 2.5 would have been fine? My main reason for even thinking of the 2.7 is mostly because I want it to last another 4 years, so I figure the faster speed may last a bit longer. However, I can save money by using AmEx points if I purchase a 2.5 online. Decisions, decisions..