Almost always weapons. Only exceptions are when I'm playing some kind of challenge that pretty much requires that I have a certain armor in order to even be able to survive against a certain boss etc. Though I try to get both as often as possible, I sometimes end up with really bad early-game armor for a very long period of time simply because I spend all my money on getting the best weapons aviable. In those games where you can randomly find awesome equipment while progressing trough the storyline rather than having to buy it, I usually don't have to worry much about it though.

But yeah, I generally priorize weapons.