Generally speaking, the more money you pay for a mic, the better sound you get. That's not the same as a flat frequency response, which would probably serve modeling software best.
My guess is, if you're asking this question, you don't want to spend much. Check out these mics: Rode NT-1, Oktava C-012 (buy it from the Sound Room unless you want to get involved in long, boring discussions in this forum trying to defend your purchase with people who think they know better), AT 4033.
They're all good mics, depending on the application. Spend as much as you can scrape together is my advice.
Of course, Regebro's recommendation of the Earthworks mic is probably way sound if you want to go noble.