What to Wear Running with Strangers

Situation
Joining a new running group; doing a Meet Up (meetup.com) or Tweet Up (Twitter); or going on a blind date with a runner (Hook Up!) means running with strangers. We've all heard what they say about first impressions, so here's some thoughts on putting your best foot forward (sorry; punny).
 It's What's on the Inside that Matters
Your appearance on a run doesn't really matter, which is lucky for me because I own (and wear) gear that is 12-years old. Real runners will care more about participation and that you keep the established pace (don't jack rabbit off or expect everyone to wait if you walk), so try to not take this too seriously! Strive to be comfortable on the outside AND the inside.

I Still Care, What Should I Wear?
1) Wear ALL three of the basics: shirt, running shoes and shorts or tights.
Many runners have amazing bodies. If you're one of them, kudos. For a first-time meeting, keep that piece of info to yourself and wear a shirt. Wear running shoes, racing flats or, if you're willing to get into a discussion, Vibram Five Fingers. Do not wear sneakers, tennis shoes or Keds. Also, wear real running shorts (see previous entry) or well-fitting (but discreet) tights. Yoga pants, sweatpants and khaki shorts have their place but a group run isn't it.
2) Dress for the weather and hold the wacky.
Wear gear in which you will be as comfortable as possible considering the conditions. If you want to be invited back, leave your rubber weight-loss suit or Halloween 10k race costume at home. This isn't just snobbery (maybe a little), it's also the fact that running with someone who seems to be working extra hard because they are too cold or hot is distracting.
3) Go with what you know. The best way to be comfortable is to wear gear that you trust and that has stood up to similar runs in the past. If that's not possible, wear something clean and that isn't prone to smelling funky.

Running with other people can motivate and, I've heard, be a great way to meet a potential boyfriend/girlfriend. Whatever you're looking for, good luck and happy running!