Oh, wow!! This is fun!!
I'd pick a three-piece. My choir boy voice, a groovy bassist and a keyboard genius.
Until you make it, I guess you have to fake it, so we'd go for synth pop covers: think Kraftwerk (The Model), Depeche Mode (anything up until the "Violator" album) and Yello (pitch shift to taste) We'd also do Boo! covers. I could occasionally pitch in on rhythm guitar – for a few laughs – and it wouldn't hurt if the keyboardist were also a hot saxophonist.
Original music is a must, and while it would have a pop flavour, I'd love to write me a Vienna (Ultravox); something deep. We'd need a gimmick, hm... Fancy dress/magic tricks/karaoke/all of the aforementioned? And a kick ass band name.
As a teenager in my first band, we looked to other younger bands for inspiration, like Ash and Silverchair. We took ourselves quite seriously. A couple of years later, tired of nonrecognition, we said let's just have fun as a party band. That was fun, but then we all got jobs. If I were to get into it again, we'd have to work smarter. Each do his/her homework, prepared to thrash things out on a Saturday, or every second Saturday. We'd also have a manager, and our own sound engineer. @V8 Thanks for starting this topic. It's fun to dream!