I won't answer which one I think is smartest because it would be a tough choice, so I'd just answer a number of people, and then I'd feel bad about whomever I'd leave out, but I will mention a couple of people that I think have been overlooked in the answers. I haven't read all the answers (because I'll just be upset that most of the people didn't include me), but based on the ones I have seen.. I'd add Penelope and variousmeats to the list.

TimeSplitters

I was going to jokingly say myself before a bunch of people unironically said it was me ... y'all got punk'd , sry (except for xvilyv, that's just rude)

Oh great... A NERD contest. Exactly what y'all need. looksatcameralikeimintheOffice.jpg

I'd vote for Slagathor too, but she's a fkn queen who's also cool and shouldn't be in some NERD contest. So as a fan? Yeah, I'm offended.

Consider this a protest

Based entirely on that one physics question I asked then either Nick or Inhahe.

Sean definitely. Tit comes a close second.

In terms of specialized knowledge: slagathor, a true lady and scholar, fun too

In terms of street smarts: sean, maybe alice or landeigestalt, dunno, let's keep this list open

That is the perfect question to create a bunch of new enemies when answered. haha! And I do probably "know" only a tiny subset of users here. But they are enough to burn a witch. haha!

Gotta be Alice. She's the smartest person I know

Slagathor and Sean. Also Nick even though he's kinda goofy.