Wearing a suit to a bar or club seems a bit too much (at least around here). I usually reserve that for weddings or a special occasion. The polo shirt deal has really run it's course. You know something is out of style when every guy is wearing it. Same thing with the sweater vests over a button-up shirt. It's just been done to death.
It's funny when a lot of guys are all dressed to impress and I walk up to a girl in a solid colored t-shirt and cargo shorts and start gaming her. It makes the other guys look stupid and reinforces to the girl that I don't care what somebody else is wearing. It doesn't affect my game.
I think I got my t-shirts 4 for $10. They're cheap, and they fit good. I'm not saying to go out and look like a slob, but the better looking you are, the more you can get away with. I certainly am not gullible enough to fall for a marketing campaign to spend $200 on a pair of jeans. If that makes you happy though, be my guest.
I would agree with the above, the fit is the most important. Even if you're wearing something expensive; if it doesn't fit, won't look good. Shoes are also important. Nothing fancy, just keep 'em clean.
I'm more of a cologne guy myself.