only store on the side if they are corked and caged. dark, stronger beers usually age better ie. barleywines, imperial stouts, imperial reds, imperial whatevers except ipa's. if it's over 8.5% and you don't mid if the hop flavor fades, then age that too. belgian ales generally age well. if they have brett, then they generally get more 'bretty'. sour beers usually get better, especially gueuzes (cantillon, tilquin, boon, oud beersel, hanssens) krieks and other lambics the fruit flavor fades and they get more sour. american wild ales like the russian river 'ations' may or may not improve. in my experience they are better fresh. they are already aged by the time they reach market.
as far as coffee, fruit or anything else, that shit fades/mellows over time. if you like a coffee stout fresh, chances are you may not like it after a year. coffee can get pretty stale tasting after too long. there's always exceptions but this is generally what i've found.