I'm runnig 18x9 with 245/45 on the front, and 18x10 with 275/40 on the rear. The tires are Goodyear Eagle F1 GS-D3. I wanted good lateral traction to improve handling in the turns, but also wanted to keep the tire diameter close to stock and have enough sidewall for comfort. I am very pleased with the results.
However, your selection should be based on what it is you want to achieve. Is it appearance, traction for acceleration, lateral traction for handling, and what road conditions will you be on. I am fortunate in that I can use a summer tire all year.
I found Tire Rack to have a lot of useful information in selecting tires.