Is it always better to just buy now and ignore marketing hype, announcements, and speculation?  If I always wait for the next model, I will never buy anything.  


What about buying the cheapest thing now as a stop-gap, and waiting until after the next big photo-show?  Or renting equipment until I find something I really like working with?  (Won't that get expensive over time?)  

What do you do when you want to get new kit?  

I would really like to hear how best to make the decision to buy or to wait.