I know exactly how you feel Arwen - it's the letting go of the hopes and the possibilities of a future that you'd barely let yourself begin to have, rather than the man himself by the sounds of it.
Pretty much the same thing just happened to me - I 'met' someone via a dating website, clicked incredibly well with him via loads of emails, but then when I met him was gutted, as I just didn't fancy him at all. We stayed in contact though, and became very close friends, emails, long phone calls etc, and decided to meet up again, about 4 months down the line.
Sadly I still didn't fancy him, even after a quick snog to make sure - but still felt like best friends. Began to realise that he had a very complex relationship with his bi-polar ex, and resolved to stay clear. He kept on chasing me romantically (encouraged I suppose by the snog) and then about a month ago, we met up again, wierdly I fancied him - we had a shag, he got all "I dont know how I fee", then invited me to stay with him and meet his dd, I did, and then he's come over all confused again and can't get his ex out of his head. So he's in the dumper, just as I'd finally decided maybe there was a future and was building up some hopes and dreams.
The point of all that I suppose is to say don't dismiss websites, though I agree with Snaf about the free ones. Even the paid ones are a bit full of people desperately projecting all their fantasies onto a photo and a few words though, and can be quite uncomfortable. I find that the people I click with are nearly always the other side of the country too. But they are a reasonable way of dipping a toe in the water, so long as you are fairly cynical about it. My man was the only one I wanted to meet over several months of being on it, but I'm not put off - sometimes you might just end up with a nice email/msn buddy, you never know. I think the best way is not to be looking for love or happy ever after, just a date or even a friend.