I have created a "practical" wish list of sorts for my camera... a not-so-exorbitant wish list (IMHO) of lenses. I didn't go so far as to pick every "L" series prime lens available by Canon. Instead, I put together a balance of lenses based on my needs, wants and budget. I can't afford all of these lenses in one go, mind you, so when I say budget I am referring to the hypothetical budget I will be building this year as I hypothetically start to see a ROI through photography.

EF 15mm f/2.8 Fisheye, $719
My most probable next purchase, this fisheye lens will have a multitude of uses for both day-to-day shots and travel photography. I can already see wet doggy nose marks on the tip of the bubble. :)

EF 50mm f/1.4 USM, $379
One day, when I can say for certain exactly how this f/1.4 differs rom my f/1.8, I will sell my cheapy-fifty for this faster, ultrasonic version.

EF 85mm f/1.8 USM, $419
This will be another first-step purchase to practice portrait photography. If this focal length proves worthy over the 135mm, I will step it up to the EF 85mm f/1.2L II USM for $2199. For now I can fake my 85mm photos with my 24-105mm f/4 zoom lens.

EF 135mm f/2L USM, $1089
Speak of the devil, here is the 135mm. I played with my co-worker's 135mm for about 10 seconds at the office before I decided that I needed a DSLR camera and I needed this lens. Amazing portrait results. Okay, maybe this is my next lens.

EF 70-200mm f/2.8L IS USM, $1999
This will be my super-duper I can take a picture of the eiffel tower from my hotel room even though I'm still in the U.S. lens. I just want it because it's pretty. *sigh*
So my to-do list will be 15, 135, 7-200, 85, 50. Actually, it will be battery grip, 15, 135, 7-200, 85 then 50. Or maybe battery grip, 135, 15, 85, 70-200, 50. Okay, who am I kidding, it will probably be in order from cheapest to most expensive. >.<