yeah I'm aware that the K version has a fully unlocked multiplier, was simply highlighting for people who hadn't seen it that even the non K version (or some at least) will have a small amount of OC headroom, albeit artificially limited.
edit: to better explain; from the table, the section in green is the stock clock-speeds, including turbo, for a stock 2500.
the purple section above is the max multiplier you can use for each turbo mode (dependent on number of cores). these speeds are manually altered, but without as much flexiblilty as the K editions.
Since a lot of people will buy the K version, I can see these getting cheaper quite soon, and for anyone wanting a cool running quad (at 3.8-4.1 dependent on load) for games, that isn't a serious OCer, this could be ideal.
In my eyes intel seem to have limited the non K version to about as far as they could guarantee they could all be run on the stock cooler, which i think is fair enough.
Edit 2: and yes in answer to the OP, the K editions are the most overclock friendly by quite some way, 9th of this month.