I agree with FreeMoney.
I think that as long as the generation reward is predictable there will be essentially no problems; people are smart, and will plan ahead. I predict the 100 blocks after the generation reward gets cut to 25BTC will be generated in the same time as the 100 block generated before the reward cut, within, oh (pulling a number out of my ear) 20% plus or minus.
I'm reminded of the Y2K hype back in 2000; that was a predictable event that turned out to be a non-event.