Your Best Friend
A strong friendship should exist at the foundation of every romantic relationship, so hooking up with your best friend isn't a completely crazy notion. "Your best friend is someone who accepts you inside out," says Amatenstein. "There can be a temptation to make it something more." But if you've been great friends for five years, ask yourself—why hasn't it already happened? Chemistry is usually undeniable.
Danger rating: High. Unless you're sure that your buddy feels the same way, you could run the risk of ruining a beautiful friendship. But if you're determined to test the waters, and feel as if you've received some positive signs, go for it. Otherwise, you may always be left wondering "what if." And if your friendship is strong enough, you should be able to move past any awkwardness if he doesn't feel the same way.
Your Vacation Romance
You're leaving on a jet plane, don't know when you'll be back again, and then bam! Suddenly, your last-minute fling has morphed into big-time love. Planning for or being on a vacation puts you in an adventurous and impulsive mood: perfect for romance. Because you initially get into it thinking that there's a set expiration date, you're less critical of the other person's flaws.
Danger rating: Low/Medium. This could turn out to be either a fond memory or the start of something major. But as Amatenstein warns, "there's no real loyalty to a meaningful relationship here, because you've just met." There's nothing to stop you from keeping in touch; just don't get too heartbroken if you stop connecting after a few months apart—and don't let your fling stop you from embracing your new local digs (and men!).