You've Got Mail or Sleepless in Seattle
I used to really love SiS, but after watching it recently for the first time in years -- Annie was a straight-up stalker! It's incredibly creepy how she goes after him like that. Meg Ryan is a beauty and the audience knows that she's a sweet, intelligent woman, but Sam doesn't. Reverse the genders and it's a completely different kind of movie.
So I think YGM is better because (a) Kathleen and Joe lived in the same neighborhood and (b) they were in the same business and (c) socialized with the same people. They would have met eventually even if they hadn't met online. Much more organic than how things transpired in SiS (I think Sam would have been freaked out by Annie and everything that she did).
The soundtrack for SiS is better, though. I also preferred the supporting cast in SiS.