I am an evolutionary anthropologist. I have two manuscripts in the wild that used Stan for modeling.
(1) An analysis of serotonin receptor variation and behavior, using Stan for some ordered logit models. Nothing fancy, just nice to have solid convergence with arbitrary varying effect structures. Also, ordered logit in Stan has been much faster for me than doing it in JAGS, I assume because of the awkward intermediate nodes needed in a JAGS implementation (?). This paper is in press at PNAS, so embargoed, but I could forward the citation along, once I have page numbers.
(2) A paper on human foraging returns across the lifespan, using multilevel gamma regressions with imputation. Most complex models have tens-of-thousands of parameters. Stan has saved my bacon, here. This paper is under review.
On the experimental end, I've gotten Stan to do a nice job on dynamic social learning data. The models are variants of "experience weighted attraction" models, with varying effects added. These models work much nicer in Stan than in other engines I've tried, I think because all of the calculations that go into computing the "attraction" scores get compiled down to lean C++ code in Stan, so aren't interpreted during sampling.
I also wrote a convenience R package, glmer2stan, to generate basic GLMM Stan models from lme4-style model formulas. This has been useful in teaching, mainly. I've been meaning to migrate it's repository over to github. So once Rstan appears there, I'll see about linking it up.