My rule is 3 weeks at room temp, then I chill one for 2 days and test it. usually its perfect.
also, some beers should be drank 'young'. very light, delicate beers, like wits and kolsch don't really improve much with months of aging. That's the little exception to the rule. beyond that, I totally agree with lemon too...most beers do better after a solid month of aging, AFTER bottle carbonation has been achieved.
and a beer that's been oaked...give it 4 months for the oaky bite to subside.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10