When to Buy a New Mac?
One of the most frequently asked questions, either to me or on web sites, mailing lists and forums is, "When are the new (insert name of product here) coming out?"
Everyone is so (justifiably) afraid of buying a brand spanking new machine, only to have Apple release a spankier one the next day or week. The problem is, the only *honest* answer to the question anyone can give you is, "I don't know." No one at Apple is going to tell you and, if you're not at Apple, you have no clue when new machines are coming out because Apple rarely pre-announces new hardware (the iPhone and Apple TV being notable exceptions).
The only advice I can ever give is, if you *need* a new machine, buy a new machine. If you don't absolutely need it, wait until the next revision of the product.
Chris H on the Your Mac Life Mailing List points us to this web site - The Macrumors Buyer's Guide. As much as I hate rumor sites, this page is interesting because it shows when the last time a particular product was revised and gives you some small indication as to when it *may* be revised again. But keep in mind their own disclaimer:
"Disclaimer: This page is based on rumors and speculation and we provide no guarantee to its accuracy. We take no responsibility for purchase decisions made based on this information.