What do you mean by hot? It gets pretty hot in the Mineshaft I hear.

Depends on how you define "best."

In general, Broad Ripple and Downtown have the largest concentrations of nightclubs ... Broad Ripple skews younger, while D'town sees a lot of white collar and tourist crowds.

I would peruse indy.com's Party Crasher galleries to get a feel for, ahem, clientele, and then dig deeper into bar descriptions / reviews in indy.com's nightlife guide

For starters, Subterra and the Vogue are generally mentioned near the top o' the list.

The Vogue is a great venue for catching live bands/entertainment. I usually avoid the crowd on other occasions. Subterra, 6 Lounge & Restaurant, Ice Lounge (downtown) and GELO (82nd and Allisonville) are all nice places that are a little more upscale, yuppie crowd. All depends on what you're looking for. Dancing? See & Be Seen? Sports Bar? etc.