I actually quite like Southwest's boarding system, where you get a assigned a boarding queue number. The numbers are something like A34, B12, C45 etc. They ask all the A customers to line up in order and then have them board, then the B customers etc. If you have status or pay extra then you get an A number. Otherwise it starts from B and is by check in sequence.
Makes it easy for the gate staff to do priority boarding (the customers just line up in order when the letter is called) and also combats the "gate lice" problem, there's no point in hovering around the gate, the boarding order has already been determined. Helps the planes get away on time as well, if you miss your spot you're at the back of the queue, so people do get to the gate on time.
Here's a little vid that shows how it works in practice.