I would rather humans drive their own evolution than remain at the mercy of nature. ;)

We kind of already have.

What current form of selective pressure is there on our gene pool that is in excess of the pressure we humans place on ourselves and our fellows? Barring some major changes, I expect other humans to remain the key source of selective pressure.

I wouldn't use the word destined, but that is neither here nor there. As technology becomes our means of adaptation, I honestly wonder if natural means of evolving become slower, though that might be a misunderstanding of evolution. Truth is we already use medication, technology, etc to solve problems for people's ways of life, and how they can live. I actually have some interest in the concept of transhumanism and although I don't think we will be having cyborgs or anything crazy anytime soon, we are already stepping on that terrority with plastic surgery, and what not. Also when we learn to work with DNA and genetics more and learn how to influence such things like we already are, it is a pretty big sign we are hijacking our own evolution already. There are going to be some pretty big issues with this however as you can see, in the past when we tried to take on the duties that nature has already taken responsibility for we usually don't start of with a efficient capacity to do so.