Got adsense cheque today

Got adsense cheque today yippee.
I seem to be on a bit of a roll the earnings are doubling each month.
I guess as my serps improve I am getting more hits on the banner ads.
I am still looking for the killer keywords that pay well
I am just targeting relevant keywords at the moment but plan to custom design a few sites offering info and hopefully they will generate some income. Everyone seems to be setting up loan sites etc.
I suspect its is why so many directories have sprung up recently they could target several keywords depending on the various categories.