Anybody who has taken music lessons at some point should be familiar with the phrase: "Those who can, do, and those who can't, teach." In cycling, those who can't, buy. And buy we do. If you can't impress your friends by destroying them up hills at races, you can always impress them with cool shit, and here's how you do it:
It's important to have a complete package. I'm talking about that guy in boulder with the Trek Madone whatever.0 with Di-2, full assos kit, and no helmet. I see that and I think anybody who can buy a $900 rear derailluer really should invest in a decent helmet. Similarly, an awesome bike can be ruined aesthetically by having one yellow tire or dirty bar tape. Just be mindful.
There's sort of a tipping point with bikes after which they become "dentist" bikes. Serottas and newer orbeas are like this. I don't care if it cost $7000. If the head tube is 2 feet long and nobody in the pro peleton rides one, it's going to be hard to impress the group. Cervelo is quickly going this way too, especially since they are so loved by triathletes, and the rich fat guy spillover has been forthcoming.
Newest and greatest is always good, but mix it up. Campy can come off as pretentious, especially if it's written on clothing, and not on shifters.
The goal is go get stuff that people will recognize as awesome, but not as overdone. This can be a moving target, so be careful. Look, BMC and Time are pretty cool, but Pinarello and especially Colnago are too dentisty. It's hard to get away with anything american, so avoid Trek, bontrager etc. Specialized has managed to lose some of the american stigma by sponsoring every team under the sun, but Cannondale still reeks of NFL and NASCAR. Somehow, high end carbon wheels are okay, Zipp, Hed, and Edge are all cool. I don't quite get why, but that's how it is. Somehow Giant bikes are allowed too, especially the newer ones with the gigantic downtubes.
There are a few bikes out there made by companies that specialize in Tri bikes that are NOT allowed. Guru, Quintana Roo, and Argon 18 just aren't going to fly with road cyclists. They may make a decent frame but we just don't care.