I had a Canon 50mm F/1.8 II but I just didnt use it enough, so I got rid of it to pay for some other lenses. I know you gain a stop or two using primes, but I prefer the flexibility of (decent) zooms, so when I was intially fleshing out my kit bag I focused on zooms.
Started with an EF-S 10-22mm F/3.5-4.5 (which I used for my
Tibet trip) back in 2007, then bought an EF-S 17-55mm F/2.8 IS and EF 70-200mm F/4L in 2008.
The 10-22s a lot of fun and I cant imagine a better walk around lens than the 17-55 2.8 IS.
The 70-200 was my first L lens (bought it second hand), and whilst the IQ is great and Ive enjoyed it out and about for a spot of urban photography, I think I wouldve prefered it to be a bit faster... although cant imagine shelling out for a 2.8 for a while!
Now that Ive got a decent tripod and all the zoom range I really need, I think Im ready for primes.
Going to see how this 100mm macro works out - if I love macro photography as much as Im expecting I will, I may buy some Kenko extension tubes (12, 20, 36mm)