A fairly common sentiment among my intro M&E students seems to be that the radical skeptic wins on the philosophical merits, but it doesn't really matter anyway -- it doesn't change what we should do in practice. Here are a couple of ways of challenging this assumption.
(1) Some (e.g. altruistic) actions are only worth taking because of their expected effect on others. If it turns out that you're a BIV (Brain in a Vat), and the rest of us mere figments of your imagination, then you'd do better to ignore the imaginary problems of starvation and disease, and simply aim at maximizing your own pleasure. If you are agnostic between the various possibilities, then presumably you should compromise in your behaviour too: donate to Oxfam occasionally, just in case, but also be a bit more hedonistic and self-absorbed than you would be if you were certain that the rest of us really existed too. This seems a pretty important practical difference.
(2) Further, what practical risks it is reasonable to take depends upon what probabilities it's reasonable to believe. You should only accept a bet, for example, if the payoff:cost ratio is better than the odds of losing -- i.e. if the expected value of the bet is positive. An essential part of that calculation is judging how likely you are to win or lose. If the inductive skeptic is right, and you have no reasonable grounds for making such a judgment about the future, then this may imply that ordinary betting behaviour is unreasonable too.
[My previous post discusses some more general links between theoretical and practical reason.]
A subtly different line of thought grants that we can't refute the skeptic, but suggests that we might as well assume they're wrong, and so carry on ordinarily. (Note the difference: the previous suggestion assumed that the skeptic was right, and sought to ignore them nonetheless. If we assume the skeptic is wrong, we avoid the above problems.) The key move here is what I call a 'practical' transcendental argument: anti-skepticism is a precondition for successful inquiry, so we may as well take it on faith. If we're wrong, we're screwed anyway; but if we're right -- if we have any chance at all of attaining knowledge -- then this assumption positions us to make the most of it.