The first three are suggestions. "You might like to" and "you might want to" are suggestions that are made polite by making them tentative. If I say "Order the fried clams," it is a command. No reason is given. Order them because I tell you to. "Order the fried clams, they're great here, they're famous for their fried clams" is an order but it's politer because I am giving a reason. "You might want to order the fried clams, they're great here" is no longer an order, because I am saying you might or might not order them. "You don't want to" is definite. It's really a command, but it's softened. If I say "Don't order a hamburger here," again, that's an order. Don't do it, because I tell you not to. "You don't want to order a hamburger here" really means the same thing, but I'm changing the emphasis to _you_ and what you want. "Might as well" expresses resignation. You don't really want to do something, but the alternatives are worse. "I'll have the fried clams." "Sorry, we're out of fried clams." "Well, then, I'll have the fried scallops." "I'm sorry, we're out of them, too." "Oh, well. We don't have time to go anywhere else. I might as well have a hamburger, after all."

You don't want to eat out? Ok, we can eat at home. You don't want to do that...you'll get hurt. You might want to write a letter to the teacher to apologize for what you've done. You might want to rethink your answer to that question. You might like to - this isn't used often. It's used more using a different subject, i.e. "He might like to go on a date with you! You won't know until you ask!" "She might like to go dancing next weekend, I'll find out." When you are speaking directly to someone, you don't say "you might like to" because you would simply ask "would you like to..?" We might as well go swimming now that our pants are drenched! I might as well go out since I've done my makeup. You might as well talk to him, he's looking right at you! I hope these are helpful :) let me know if you have anymore questions!