I believe in most cases initially one gets assigned to you (not a good one either) and that's just how it is. Rarely do junior pilots have any leverage in their domicile. As you gain seniority, yes you can wait for what you want and bid for it. The good thing though about airlines is that unlike in the military, as I'm sure you know, you don't have to physically LIVE where you are based. If you fly for AA for example and live in Dallas (where you hope to be eventually based) but are initially based out of DCA or something, you can remain living in Dallas and just commute to your base at DCA. Granted this might take a day or so out of your days off but no moving pains!