Yes, you read that right: I love taking pictures in and around parking garages. I attribute this partly to being raised in Los Angeles, where garages in general are much like a second home (and where, for the unfortunate, they actually are home).
It may also have something to do with the industrial arts (a.k.a. drafting) class I took in junior high school. I had to create drawings of buildings and mechanisms from various perspectives using nothing but a pencil, T-square, triangle, and compass. A year of that will give you a deep appreciation for lines, angles, curves, mass, and shape--either that, or you'll hate it and turn to landscape photography. You can see what path I took.
The trick to getting good photos in a parking garage is knowing how to deal with extreme contrast. The light inside the garage can be quite dim, while the light outside can be five stops brighter. You could go the HDR route to open up the shadows and reduce the brightness range to something printable or you can do as I do, which is to expose for the highlights and let the shadows go black. I do this as much to hide a garage full of boring suburban SUVs, sedans, and minivans as for its graphic effect.
Another thing that helps is a tripod. Given that I'm in or near a garage, I'm generally near my car. My car has a trunk ("boot" to you Brits) that in turn contains my tripod. The tripod allows me small apertures for more depth-of-field and low ISOs for maximum image quality. A tripod also makes it easier to make sure that everything lines up exactly the way I want it, shot after shot. Just remember to watch out for passing cars. Not only could one of them crush you under its wheels, what's worse is that it could shake the tripod and ruin the shot.