Fucking is a self-centered act, based on a lustful desire to get laid. It's usually somewhat animalistic in nature, as in "fucking like bunnies". The whole point of fucking is to relieve your pent-up sexual tension.
Making love is a gentler form of sex, involving love instead of lust, where one spends more time paying attention to his or her partner's orgasms than to their own. It's a lot like snuggling that just happens to involve sex.
They both have their place, sometimes you want to be sweet and make love, and sometimes you want to dig in your claws, let your inner beast take control, and fuck like crazed weasels. Just remember that your partner gets to do the same, so don't bitch about it when you wake up with bite marks and scratches...