You have to work out internal rates of return for both sorts of project, taking into account available data, overconfidence and other biases, etc. If you spend $50,000 on VC investments, what annual return do you expect? 30% return on investment, up there with the greatest VCs around? Then consider research or other projects (like the Singularity Summit) that could mobilize additional brainpower and financial resources to work on the problem. How plausible is it that you can get a return of more than 50% there?

There is a reasonably efficient capital market, but there isn't an efficient charitable market. However, on the entrepreneurship front, check out Rolf Nelson.