As this subject has been a bit neglected I thought I would put my two pence worth in

There are several factors that will effect the quality of your whole/ground spice collections.
Spice enemies
1. Exposure to air. (Causes oxidation which leads to loss/changes of flavour)
2. Light. (Causes colour loss and loss of flavour)
3. Heat. (Accelerates the last two factors)
4. Moisture. (A killer, it will cause mould and bacterial growth)
5. Age. (Causes colour/flavour loss and general deterioration)
Spice containers
The perfect spice container would be tube shaped (less spice surface area to contact air), air tight, water tight and opaque, unfortunately this shape is also a pain in the rear end to stack/store in a cupboard, they take a lot of room.
I use Lock 'n' lock containers, they are very secure and stack well to save space.
I keep them in a dark cool cupboard well away from the cooker.
Use small containers and try not to buy more spices than you think you will use in the next six months (whole spices will keep longer than ground)
Keep an eye on how long you have had the spices (I put the date on each container when it is refilled) and renew them regularly.
The worst case scenario is probably a nice spice rack with clear glass containers kept next to the cooker, so if your friends/family want to buy you one as a pressie to indulge your curry passion, carefully decline

My collection
Hope this has been of some help and yes, that is Bombay duck on the right, I happen to like the stuff

Jethro