Keystone Light/Natural Light—The college boy.
Even if you don't remember the nights, everyone knows the scene: Crowded frat house, beer pong, binge drinking and keg stands. If he's still drinking Keystone Light or Natural Light he's still in a college mentality. And that's fine... if he's still in college. If not, you might want to ween him onto a Bud Light—for more than just his drinking habits. Someone like this will still date like a college student too, which can be good (afternoon delights) or and bad (forgetting to call for a week). UK Study: Binge Drinking Can Lead To VD And Pregnancy
Pabst Blue Ribbon—The hipster.
This isn't necessarily a bad thing. There's a lot of things that used to be popular that aren't anymore. Granted that's usually for a reason, but with PBR making a counter-culture comeback it's easy to pick out the counter revolutionary in our midst. A PBR drinker is going to be more sensitive to your needs and want to take time to please you. The down side is he might also be emotionally dependent.
Readers, sound in: what does a man's beer say about him?