All rom-coms are fantasy. To hope for otherwise lets you in for alot of disappointment. Especially in an LDR, which is not reality either.You only need to read the romantic thread to see that...
Just to be a tiny bit of a devil's advocate: Of course they never bother with the visa process, expense of hopping on planes, etc, but I think little bits and pieces of them are real. When I first met my now hubby, yes it was the first flush of romance, but it was my reality at the time and it did feel like a romantic comedy film. (And I was lucky as the long-distance part of our relationship didn't last very long.)
Anyway, I kinda liked The Holiday, though I thought it could have been better.