Well, from a Christian perspective, sex is a gift that should only be opened on the wedding night. Christians have alot of reasons why pre-marital sex is bad (i.e., you could get pregnant, you could get an STD, you're being used, it isn't for procreation, etc.) but these are simply fabricated or exagerrated claims to add to the only Biblical reason. There is only one reason why the Bible says to not engage in fornication - because God says so. Christians tend to add more to the list of reasons, but those are merely speculation and opinion. It makes it more believable than simply saying, "well, because God says so".
This is the way I see it. Coming from a woman who was sexually promiscuous for several years and a woman who lived with her husband prior to wedlock - I can say that there must be balance. Sexual promiscuity, in my opinion, is a form of emotional and physical bondage. I used to think that being sexually active with many different partners was liberating. In truth, I was betraying my feminist beliefs and had enslaved myself as an outlet for men's sex drives. I sacrificed my integrity and my self-esteem because I was under the delusion that if I had sex with alot of guys on the first date, I would keep them interested in me long enough to find the right man for me. Problem with that was, they didn't stick around long enough for me to get to know them and they weren't interested in getting to know me out from underneath the bedcovers. In that respect, what I call "serial-fornication", is not healthy emotionally or physically.
Now, with my husband I held out on him for a year and a half. Being a man

he wanted to have sex with me, but he respected me enough to honor my request that we wait and cared about me enough to keep coming around not to get in my pants, but to get to know me. We didn't have sex until he declared his love for me and we made a serious commitment that would ultimately lead to marriage.
I want to remind those who claim that you have to sleep with alot of people to be good in bed that everyone is different. Just because I may have slept with a guy who liked his ears licked doesn't mean my husband likes it (which, for the record, he does not because he's ticklish). Being good in bed is something that two people, committed to their intimacy, work to achieve together. It's not about who can bring what skills to the bedroom. It's not like if Susie has been with eight guys and Ted's been with twenty women that having twenty-eight prior sexual partners between the two of them means they are going to be immediately good at sexually pleasing one another.
I would like to add here that there is a big difference between sexual skills and sex drive. I do think it's important to know what level of sex drive your spouse-to-be has. I know as the go through the years, sex drive changes, but it's horrible when one spouse wants sex all the time and the other would be satisfied with a once a month thing. Sex drive is not something that can usually be altered (unless someone's sex drive wanes due to mental or physical illness). Sexual skills can always be learned.