welcome tacox :welcome
think of things that cost a lot of money and you have an idea of what high paying keywords.
you can alway open up a google adsense account and play with the bidding. that is the best way to get an idea of what the big money keywords are.
traditionally there has been a lot of money in prescription drugs, special law services (for class action lawsuits) and services like webhosting which have a lot of competition and subsequently attract a lot of bidders.
so any subject with a crowded field of advertisers is what you are looking for.
Overture provides tools that allow you to see actual bid for different keywords, obviously it isn't the same as on the Google network, but it can give you a rough idea.
