You don't have a choice if you want to play online with Live (free weekends and playing as a guest aside), but then I don't have the choice of paying a fee and getting extras on PSN that make it as good as Live. I'd love to have that option, cos I might actually start using my PS3 online for games other than Fat Princess (which isn't exactly a shining example of PSN's quality I might add).
If free online was that important, millions of people wouldn't be paying for Live Gold and there'd be a lot more PS3 owners and far fewer 360 owners out there. I don't care if online is free if I can get a more fully featured system that I'll use throughout the life of the console, making the whole experience better, for 50-60 pence a week (i.e. fuck all). I spend more than 12 months of Live costs on a night out down the pub. If it bothers you so much, sell your 360........oh wait....you'll need to actually buy one first.