A little common sense goes a long way
The good news is, it's not complicated - four storage tips will have you and your chocolate in prime eating condition.
1. Don't store chocolate with strong odours.
2. Chocolate doesn't like extreme heat.
3. Or extreme cold.
4. Never eat chocolate straight from the fridge.
Let's start with odours
If chocolate is near strong smells, it will absorb them. So keep it separate, or in an airtight container, if it's mingling with smelly friends.
Unless of course you want your chocolate to taste like blue cheese or garlic.
Then there's heat
It's not a stretch to know chocolate melts in heat (in fact it starts to melt at 37 degrees) so the ideal storage is a cool dry space, like a kitchen cupboard.
Exposing chocolate to heat can cause that weird white 'bloom' you've probably come across on chocolate. When it's heat related, this occurs because the cocoa butter separates from the solids. In theory it's safe to still eat, but I've never felt it tastes the same or has the same texture.
Keep it cool...
... just not cold. Chocolate likes to be comfortable, and like it doesn't enjoy extreme heat, neither does it enjoy extreme cold. Which means don't store it in the fridge as it's too cold and humid.
Which leads us to the second type of white bloom. If your chocolate has white bloom AND feels rough to touch, that means it's been exposed to moisture and you have sugar bloom. This may occur from humidity, or perhaps rum and raison chocolate where the rum has leached into the chocolate.
A cool dry place is perfect
Of course, if it's the height of summer and there is no cool dry place left in your house, store it in the fridge - this is preferable to melted chocolate. However ALWAYS take it out an hour or two before you want to eat it. Chocolate, like red wine and cheese, should always be eaten at room temperature. The cold will adversely affect the flavour and texture.
The one exception is if you have a wine fridge, the temperature and humidity is quite good for chocolate. I personally store my chocolate - bearing in mind I have a lot of it due to my business - in a climate controlled wine storage unit. But still let it come to room temperature before eating.