Can I use an espresso blend with an aeropress? I've heard that for a quality cup of aeropress coffee, one should be only using single origin coffees. I was wondering what the advantage of using single origin coffees was over espresso blends when brewing with an aeropress.
The answer is quite simply: It's up to your personal preference.

Lots of things make a good cup of espresso; some people like (or think they like) single origin expensive marketing-buzzword-infused coffees, and others have found other roasts / blends that work just as well for them. You can use whatever you want in your aeropress to make a cup of joe that suits you.

As this question on Seasoned Advise suggests, there are some objective measures we might look at. Since and Aeropress (disclaimer, I don't have one, but I have used them while backpacking quite a lot) tends to extract a lot of flavor, a medium roast will probably prevent your coffee from being too dark, and still provide a lot of flavor. You'll also want a nice fine grind, which is generally what you want for any espresso machine.