With desktops, there's very little reason to wait for several generations (or even upgrade for that matter) unless it's for new technologies like USB 3.0, PCI-E 3.0, etc... Intel is heavily focused on investing in making better mobile chips with better IGP performance, lower power usage, and features like "connected standby". Almost none of these matter in a desktop where you're likely to have a dedicated GPU and can suck down all the power you'd like.
+1
All I see is intel heading in a direction that is not in line with desktop performance. Future improvements will be in power usage (TDP ect) and onboard GPU. The processing improvement will be rather small in comparison.
as to upgrading, only do it if you need it.
PCI-E 3.0 too new and no noticable video cards using it (and even less other devices)
USB 3.0 getting to being usable but that has taken over 2 and a half years from inital release. (
http://en.wikipedia.org/wiki/USB_3.0). If you have managed to do without it for that length of time, another 6 months is not that big of a deal.
I personally have only upgraded from my q6600 as I was bitten by the upgrade bug about 8 months ago, but waited for SB-E (let down ways), waited for the cheap SB-E, waited for Ivy, waited for the motherboards to be tested by other users (not interested in a SB release issue again). All that with the GFC issues going on resulted in finding another reason to delay upgrading.