I'm going to disagree with some folks here. I think the 60mm EF-S lens is a fine choice for a first macro lens on a crop frame Canon. Yes, the working distance is a bit less than the 100, but it's just as sharp (or so close you won't notice the difference), lots lighter and quite a bit cheaper. The only really strong argument against it is the fault of all EF-S lenses - lack of compatibility when/if you upgrade to full frame. I'm not saying the 100 (L or non-L) are bad choices. They're both excellent lenses, but I just think that a beginner can get more bang for the buck with the 60.
If you really want to just dip your toe in the macro waters then I agree that a set of extension tubes on a normal to short telephoto lens is a cheap approach. I shot with a 50/1.4 + Kenko tubes for a year before buying a macro, though, and while it works it's MUCH less convenient and flexible than a dedicated macro lens.
Ultimately though, the correct answer (as in most "what lens should I buy" questions) comes down to what your intended use is. If you want a medium focal length lens for general photography and whatever close up shots come up then the 60 EF-S (or 100L if money is no object) are good choices. If you really want to shoot small critters then a longer focal length option like the Sigma 150/2.8 would work well and would provide enough working distance so you won't scare off every bug you try to shoot.
There are more exotic/expensive choices if you go deeper down the macro rabbit-hole, and you'll soon find that accessories like a proper macro flash are desirable. But start with a simple, sharp macro lens like any listed here and then see where your shooting takes you.