I've never aged beer for more than a few months before, but I might need to find another level of patience. A friend of mine had several left from last Spring, when I was in Omaha last.... I've had a couple of of Bourbon County Stouts that have been fantastic, and I'm drinking an Oak Aged Espresso Yeti right now that's smoothed out from almost all oak to a nice balance of coffee and oak... really damn good.
I've always read great reviews after aging stouts for a year plus and have had the intention of aging a few... I'll definitely be sending one or two to the basement for now on.