I don't have them on my car. I was really close to getting them when I still had my stock rims on all the time. They will push your stock wheels out and give your car a wider stance.
If you plan on getting new rims in the near future, I wouldn't worry about getting spacers. The new wheels will probably be wide enough unless you want them to be out more, though I think flush with the fender is as far as you'd want them to prevent damage to the paint.
H&R makes good wheel spacers...their hub centric ones will fit stock or aftermarket wheels. Some other brands don't always fit stock wheels, some just work with aftermarket ones, something to keep in mind. 1" spacers will push your rear wheels out to the fender.