The .30-06 has always been a great cartridge for many reasons - not the least of which is that it gets the job done reliably without excessive recoil. The introduction of better bullets, like the Partition, improved its capability and modern bullets, like the A-Frame, Trophy Bonded, North Fork, TSX, Scirocco, AccuBond and InterBond, coupled with modern powders, have only solidified its position as a 'still capable' cartridge.
The fact of the matter is that the '-06 will suffice for just about every North Amercan hunting need. They say a man who has a .30-06 doesn't need anything else. I think this is as true today as it ever was (and the best argument for not owning one!). No, it woulldn't be my first choice for grizzly, but it would be far from my last - and if I had to stop a charge with one, I would be focused on shot placement rather than worrying about the adequacy of the '-06.