What are the hottest, most profitable topics to blog about?

I would say making money would be the best way. Working from home, finances in tough times, so on. With the unemployment and such going on, I think that is probably something searched for a lot. Would make even more money, if instead of listing the typical MLM and such, that real at home jobs were provided, sites that you were sure were not scams, and anything that does not require a fee. If you have good information, and a lot of it, people will link to you a lot in forums and such. Sexuality is something that people look for a lot as well. Politics always has a good following. I think the safest bet though, is anything money related.