Yes, the trust fund does exist but it is money owed to the government by the government. So any balance in the fund is only on paper. What truly matters for the government is the cash flow perspective: when annual payouts exceed incoming funds (which James pointed out will be happening soon). How does the government make up the difference? It cashes in the treasury securities to itself. The treasury gets the money for the sold security by selling DIFFERENT bonds which ultimately get paid of by the Fed printing more money since we run an account deficit.
Despite what the Fed says, the likely plan to resolve all of our federal debt issues (including SS) is through inflation. This doesn't require political will as there is no need to cut benefits or raises taxes, just limit COL adjustments to "core" inflation so effective payout is less than real inflation (this change happened a few years ago). The recession was the opportunity to increase the supply through TARP and "quantitative easing", now there just needs to be a stabilization of the credit markets to get that money moving. Of course, the problem with this plan is that the national debt is growing FASTER than inflation and will continue to do so for the foreseeable future because of the REAL giant elephant in the room: Medicare.
So to respond to the OP, yes I expect to get my fully committed SS benefits but I do not expect them to have the same purchasing power as today (I assume a 50% "real" value for those benefits). I also reduce my expected returns by another 50% since I don't plan on working past 45 which will reduce my benefits. Overall, I assume a net of 25%, which is more like the dessert than the meat and potatoes of my retirement plans.
Sidenote: The supply of money has increased more than 60% in the last 10 years (
http://seekingalpha.com/article/258513-exploring-money-supply-over-the-past-10-years-through-charts. To this point in time, real inflation has been relatively tame over that time period due to the recession (since inflation = supply x
velocity, velocity is limited by the credit markets currently). Once the world economy stabilizes, look out for inflation.