I store quite a lot of beer, and I think somewhere around 9% is a good ABV to suggest good aging. Heavy stouts, barleywines, and the darker belgians all age very nicely. Cheap barleywines in particular, such as the Sierra Nevada Bigfoot or Stone Old Guardian are totally different beasts when aged for a year or more (up to 10, although diminishing returns probably set in at around 3 years). Strong stouts age up nicely in about 6 months, and in general I wouldn't give them more than a couple years. I haven't stored many dark belgians since they're not my favorite style, but I've heard that for example the Chimay Grande Reserve takes about 3 years to really change its stripes.
If you have a beer that's lighter in color and slightly lower in ABV, and question storing it, check for a yeast sediment on the bottom. Ommegang Biere De Mars for example is light in color and 6.5% but ages nicely because of the added yeast in the bottle. As a general rule, the thicker and sweeter the beer the more it will break down and taste better over time.
Not sure about storing after refrigeration. I keep mine at FL air conditioned room temperature (78 degrees) in dark boxes and haven't had a bottle go bad yet. All the cellaring guides suggest 55 degrees for storage but up to a couple years I think I can get away with the higher temps since I'm not interested in aging more than a year or two.