Incline will not hit more muscles than bench, however, flat bench is not "all you need." Incline and flat bench can be done on the same day, or on separate days depending on your routine.
Your next question will probably be "Well, what do I need?" My response is "What you need to do, is stop running, and do one of the two routines listed in the FAQ. If you do MMA stuff, do the two day a week routine. The info in the FAQ is very high quality. 'How high quality?' Well, if you would stop going on the internet, stop reading anything on weights except the FAQ, follow what it said, progressed by +5lbs every workout on your lifts, in 3 months you will be much stronger than you were and you wouldn't have to ask questions like 'What does incline do for you and is it better than bench?'
The FAQ is all you need. In addition to reading it, you must follow it. But you probably won't. Your going to go to bb.com and follow some shit there. Fine, but when you are still weak, come back, follow the FAQ and get strong. Of course, there is the chance you are a pussy and will quit all your training in a month or two.