Durable, AA, 2 mode clicky, ~$50, the first thing that pops in my head is the Fenix TK20.
4 Sevens is also having a sale on quarks right now too, if you get the tactical version, it will in a sense be a 2 mode light.
You could also get a nitecore D10 from 4sevens for just slightly over $50 w/ their discount. although the whole ramping UI may seem a little confusing at first, it is very simple to operate as well as go from just low to high
A zebralight H501 is also a good edc if you wanted a floodlight, although it has 3 modes
For AAA's, I like my Fenix E01 and LD01 Stainless (although that one is 3 modes also). They're both solid. You could wait on 4sevens Preons as well