My general rule of thumb is to raise 3x + 1x for each limper in front of me up to 5x. As for what hands I raise with, I'm sorry, but I refuse to define my exact range. What I will say is that I usually don't play any hand that I wouldn't be willing to raise with. But it's also important to keep in mind that not every hand that I would raise with is necessarily a hand that I would call a raise with. Nor do I consider every hand that I would put a 3x raise in with to necessarily be worth raising 5x with. For example, I might look at a hand toward the bottom of my raising range and have every intention of making a 3x raise with it. But before action reaches me, three other players have already limped in front of me. While I might consider that hand worth making a 3x open raise with, I might not think it's worth making a 5x raise with, considering that between the limpers and the blinds, it's possible that more than one player might find themselves tempted to call. But I still won't limp. And knowing that a 3x raise will probably not be enough to discourage a player that has already committed 1BB to the pot, I am more likely to just fold than to make a 5x raise with the bottom of my range.
The point is to make it expensive to see flops with weak hands. I take pride in my ability to shut down bingo play when I'm at a table. I've found that players will soon become reluctant to continue with the limp into every pot with any two cards strategy once they realize that they are throwing away chips by limping and then having to fold or call a 4x or 5x raise with weak hands. As for players that seem determined to see the flop with weak hands, since, considering my range, it's likely that I will be have the better starting hand, it's also likely that if we both get a piece of the flop, I will likely have the better hand post-flop. In which case, I'm going to continue to make them pay for playing weak hands against me. This will further discourage them from trying limp into pots with weak hands.
