Absolutely women and men can be friends.  Some of my best friends are guys.  So many times girls are, well, just plain bitchy.  I'd rather hang out with a group of guys because (my friends at least) are fun, laid back, aren't trying to hump anything that walks by in a skirt and just are really cool people.  If we get pissed, we tell each other off, and the next day its like nothing ever happend.  
Plus, its kinda fun to be "the girl" and get the attention for that