If this was my main hobby there would be nothing anybody could say to stop me upgrading once a year, on every new product cycle and buying all new top of the range kit.
As it isnt anymore, then once every couple of years is enough for me now, sometimes even then I dont as the cost doesnt justify the performance increase any more.
I think thats the stance everyone should take to be fair, if its your hobby and you can afford it, then go for it, as I would.
If it isnt or cost is a factor in your decision then yes, you are better off waiting as you will simply not be getting your moneys worth.
For instance, I had a Q6600 at stock speeds for 3 years till august last year, it never struggled actually running anything when it was tied to a decent graphics card.
In August however I just fancied some new gear so spent £600 on a 2600k a new mobo, ram, memory and HDD.
Last weekend I spent another £300 on parts, new case, new cooler, some corsair Dominator GT ram so I can get into overclocking and fiddling again.
I dont think however, even though I could flog out the Z68 V-pro, the 2600k and the ram, and make the majority of the cost of a new Ivy bridge set up back, that I could justify doing it, even though I'm going to have the entire machine totally apart this coming weekend.