All, thanks so much for all the info.
As for the macro rails, I think I will buy only after I physically see them. I don't want to spend $150 and then find that I should have saved and got the $350 ones. I guess I'll shoot macros hand held for now as suggested by drjlo. And there is my trusty tripod too (though it may be 30yrs old).
As for extension tubes, I think Kenko air is not significantly cheaper than Canon air (here in India) and since no shops (that i know of) stock Kenko, I will get me some Canon air...