I expect I'll keep going until such a time as I've completed the pokedex. Since it's possible to get just about everything with enough eggs, I'm unlikely to lose heart because something doesn't seem to come up where I live; it'll just be a matter of time until I hatch whatever I need. I probably won't worry too much about the region-exclusives and stop playing so much when I have everything but them, but if ever I travel to another region I'll whip my phone out and have a look around.
All that having been said, I'm only on 60 or so in my Pokedex, and I fully expect that gen 2 will be released before I find all the gen 1 ones and render such questions moot :P