Something is only worth what someone is willing to pay for it. Some might pay full price, others might wait and some won't buy it at all.
None of these choices need a defense. If you want to wait, then wait. That's your choice, no one cares what option you go for. I'm going to pre-order it, then it's done and I can forget about it til it drops through the letterbox.
Im sick of reading comments about Zavvi's pricing. They're no better or worse than Amazon or HMV. If you hate them then fine, don't buy from them, or wait for a price you're happy with. Personally I don't like being told what I should or shouldn't pay for something. It's my money and I'll do what I like with it.