The cooler your storage the better. If you can store in the fridge you should have no problems storing your beer for two months. If you don't have the fridge space, try a cool basement. Just don't keep them in your 90 degree garage, and you should be fine.
Stronger beer styles will keep just fine for two months and even several months longer. You might notice some flavor degradation in delicate light beers, and more hoppy beers might start to lose some of their fresh hop character. Many people probably won't notice the difference though.
In general, commercial beers will probably keep better than home brewed beer because commercial brewers are very conscious of things like minimizing oxygen uptake which slows staling. Commercial brewers also often filter out yeast before bottling (unless they bottle condition) so you might not have dead yeast in the bottom of the bottle adding off flavors as the cells break down.
The Homebrew Nerd