I wasn't aware you're not in the US. If your country has high capital gains taxes compared to income taxes, the balance might be different in the US. However, stamps and other collectibles have many problems:
-- Stamps can get stolen, lost, or burned in a fire. It's hard for this to happen to stocks (unless you're behind the times and have them as a pile of paper certificates)
-- If you buy a type of collectibles that you're actually interested in, your desire to keep a co llection of something you're interested in may lead to poor decision-making on a financial level
-- When buying stamps and other collectibles, you generally have to pay retail prices, and when you sell them, you only get wholesale prices. And you can sell a stock any time; selling a collectible is a big deal and takes effort.
Also, I find it very doubtful that stamps aren't subject to inheritance or estate taxes.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.