The formula for the songs I like on the radio right now are a female chorus with rap lyrics. The two songs are Airplanes (by B.O.B. featuring Hayley Williams) and I Love the Way you Lie (by Eminem featuring Rihanna). I'm just waiting for a Christian female singer and Christian rapper to get together and use the formula for a Christian song.
The thing about formulas is that when they work they work, however, they only work for so long, because soon people get tired of the formula.
I think about the formula I use for preaching, its basically:
1. Catchy Introduction (that connects with the text and point)
2. Something personal (If I've dealt with it, most likely, someone else in the audience has as well)
3. Scripture (Explanation of context and gist of the text)
5. Conclusion (Ideally one that bookends something from the introduction)
Its working so far, but I do look forward to trying new things to keep it fresh.