Easiest ones first. The more algs you learn, the easier it becomes to learn more.
Completely agree with this.
I've only been cubing for about 7 weeks, and fairly recently learned full PLL, so I think I have a fresh perspective of what it takes to get the algs down (at least for me). When I first started learning full PLL, it took a while to get them to a comfortable state in which I could recognize the case, recall the alg (or first few moves), and perform the algorithm in a fluid process. It was a two-part process, first memorizing the algorithms, and then committing them to muscle memory. As I've become more familiar with algorithms, and efficient ways of performing certain patterns, those two parts now happen simultaneously.
As far as what order, I learned them in a pretty haphazard fashion. I knew a U and A from the beginner's method (badmephisto), and so added those first. I noticed that the T, F, Y, and Jb algorithms were very similar, so I learned them all at the same time. The rest I picked up as I went. If there was an algorithm that I hadn't learned yet and it appeared comfortable to perform, I set it to memory. I learned the Gs last, partly because they seemed to be harder, and partly because I didn't like algorithms that require cube rotations. I've been using the G perms from TellerWest's youtube page. I doubt that I could've picked them up quickly when I first started with full PLL, but it only took a couple days to feel comfortable with using them.
I think the specific order doesn't matter all that much, but I do think that going from the easiest algorithms to the more difficult is probably a more efficient way of learning them. By the time you start learning the harder algorithms you've developed some skills to speed the process along.