I'd say that it really depends on the sort of coffee you like. Both are great and I'm glad that you're going that direction. Here's my recommendation:

• If you like French press coffee, go for the moka pot first. To me, it's somewhere between French press and espresso; somewhat acidic and strong but not extracted with enough pressure to be espresso. Also, like espresso, moka pot coffee is best served in small portions.

• If you prefer drip or espresso, go for the aeropress. Depending on technique, you can get some good crema and nearly proper espresso as you can generate much more pressure than a moka pot.

A couple of other thoughts: make sure that you have a good grinder, I like burr grinders. Also, if you really want stovetop espresso, something like Bialetti's Brikka might be worth checking out. I've but tried one yet but, they use a similar weighted valve system to old-school pressure cookers that allows the coffee maker to achieve proper espresso pressures.