In a business climate where there are challenges from so many directions, it is essential that each organization make intelligent choices with respect to how they approach and execute the resources they are directing toward internet marketing. Should you be putting your energy into Social Media, PPC, Analytics, SEO (again), etc?
My feeling is that each of these areas can work for any company at any time, but to a large degree the low hanging fruit has been skimmed and developing a profitable initiative is more difficult in a general sense. So, it is not so certain that any one effort, i.e. creating a Facebook marketing campaign or re-optimizing your website will prove worthwhile in comparison to the time and money involved. That doesn't mean you ever want to stop trying new things for your site, and budget aside, you should be attempting all of those tactics, but cost /benefit projections should be factored in, to the degree possible.
What then would be an investment that would be more likely to pay dividends in the future? I suggest the answer is as obvious as the iphone or blackberry in your pocket. Although I don't have specific data to support my case, I would wager that on average the companies who were the early adopters of the web in general are ahead today of those who got on board later on and for whom the catch-up curve has proven to be steep (from an opportunity cost perspective).
What is to me, so "in your face" obvious is that the mobile internet represents a chance for companies to regain that edge. I am not suggesting that mobile will become a meaningful revenue stream for your business anytime soon, so it's not prudent to take the eye off the ball of your website in any way, but I can project with certainty that any efforts you put into experimenting with mobile will have a multiplier affect more so than incremental dollars directed at any of the channels you have been chipping away at for the past 8-10 years. On top of that, the expense associated with gaining an initial mobile presence is incredibly nominal.
Having a basic mobile presence may not yet be a necessity, but it is well past the point of being speculative. Gaining a foothold now will be instrumental to how well you are positioned from a competitive perspective moving forward.