Every time someone asks me the question in general, I pretty much have to say something like, "I got AA's as each expansion released them so I never had to deal with prioritizing all of them at once." Which is literally true in my case. I remember when maxing out at 300 AA's was considered impressive.
That said, this thread is worth skimming through at least. It's old advice, and a few things have changed, but the concepts remain valid...in particular that your playstyle determines some of your priorities. There are other threads in this section worth looking at, such as
http://beastlords.org/index.php?topic=8701.0.
If you're looking for something that's less than years old, you aren't going to find it all in one spot. Info on the last few expansions is likely only going to be in threads that discuss that expansion.