I live in an area with lousy dating opportunities, so I've thought a lot about long distance dating. I think it's hard to develop true depth in a relationship if you're not spending time together. And, quite honestly, I want a partner to engage with, who does things with my friends, etc. I don't want to be spending my evenings at home on the phone. I think long distance is doable if the relationship is casual. Otherwise, I'm not so sure.
I'd pretty much rule out anyone outside of reasonable driving distance. In my case, if I met a great guy in Sacramento or San Francisco, I'd probably give it a shot. As soon as air travel gets involved, it becomes more complicated. He'd have to be truly AMAZING for me to work that hard at it.
Early in a relationship, long distance dating is a big commitment, expense, etc. If you've been together for years and you need to spend some time apart, that's one thing. But the beginning is always the "getting to know you" part. You've really got to ask yourself if both people are willing to invest enough time and energy to see if it works. Otherwise it's not worth doing. And then there's always the emotional toll of being separated, not seeing enough of each other, etc.