See also: Numismatics
Possibly the world's least cool hobby, I've had a mild interest in stamp collecting since I was about ten that flares up periodically. The most recent of these outbreaks happened because I was attempting to clean my apartment and discovered a couple bags of used stamps still on paper.
I've been aware my entire life that stamp collecting isn't a reliable investment, but this was still a bit depressing to read:
Mint with original gum US postage stamps printed in the last 70 years are, with a few exceptions, worth less than their face value and can be used for postage without worry. I use old stamps back into the 1930s as postage to mail envelopes. ... Unfortunately, many collections have so many modern mint stamps that there is no chance to actually use them all even in a few lifetimes! This is why people routinely sell stamps at far below face value (many stamp dealers offer 50-70% depending on their customer base, how much postage they already have in inventory, and what denominations are included). They will then either use it for postage or resell it at 75-90% of the face value to buyers that use it on mailings.
The stamp collecting boom of the 1930’s resulted in countless thousands of collectors hoarding newly issued stamps the US Postal Service issued. This kicked off a positive feedback loop that prompted the USPS to design and print more stamps to meet the increased demand. The net effect is that virtually all US stamps produced since the 1930s are available in quantities that far exceed collector demand so stamp collecting values have suffered.
I imagine that what s/he says about American stamps applies equally to Canadian stamps. If you collect stamps, you do it out of personal interest - not for money. My collection, having lived in Canada and the U.S., is strong on Canadian and American mint stamps from the 70s forward. Which is to say, it's utterly worthless.
It can still be interesting: you can collect mint stamps, or used, or imperf. Definitives or commemoratives. You can collect queens (not that kind ... or maybe you can), Georges, nature, aircraft, space, collector sheets, Newfoundland, or stamps with holograms. This one made me very happy:
I quite like this type of spider (see my bad picture of one).
If you choose to concentrate on Queen Elizabeth II, she comes in an infinite variety and you might want to narrow your focus:
There are hundreds of stamps with Queen Elizabeth on them in Canada - this is only a couple of series. Similar series are repeated throughout the Commonwealth: Australia, Barbados, many others, but most notably the U.K. which represents their monarch on stamps in a dazzling variety that Canada cannot compete with. And then you get into historical accuracy, because some of these were published while she was still Princess Elizabeth because her father George was still alive. George is of course a good subject too:
The above is a bit of a cheat: these are mostly George the Sixth (Elizabeth's father), but I snuck in one of George V as well, and one is from the U.K. rather than Canada.
But it's not all formality:
This particular one is a lot of fun: it wouldn't happen in the U.S. or Canada. Since commemorative stamps became a money-maker for post offices, art has been popular on stamps in the last several decades: it's another good topic to collect, probably more interesting than definitives with royalty on them.
- the above sites are quite good, but so far the best method I've found to identify a stamp is to type any words or identifiable features into a Google Images search and then visit websites that have photos of the stamp