When I was early in my graduate program in a small college town, I used to say that my sojourn in a small town would be temporary. I'd get through my program, land that degree, and I would go on the market and look solely for jobs in big cities, and in a part of the country where I'd be able to stay close to my friends and family.
The reality of the academic job market looked much different. For every hundred job posts in my field, there were probably only 30 or 40 that were in geographic locations I'd consider living. Among those 30 or 40 jobs, there were only a small portion that were either open to any specialization or that were specifically looking for someone with my specialization. Some of those 30 or 40 were at the type of schools that I didn't want to work at or wouldn't be qualified to work at under any circumstances (don't misunderstand the market ... the ranking of your graduate program matters).
If there were thousands of job listings out there that were being constantly updated and refreshed, this might not be a big deal. But the academic job market has gotten tighter and tighter each year, with fewer and fewer jobs posted every season. So you'r not choosing between hundreds of jobs if you limit yourself geographically. You're choosing between "tens" of jobs.
And, of course, you aren't really choosing ... they're choosing you. And likely, they're considering you from within a pool of hundreds of other applicants from different graduate programs, as well as current professors and postdocs looking to change jobs. So your chances of getting any particular job is pretty miniscule, and pretty random. Even the top student in my program wound up taking a position in a geographic location (and in a far less prestigious school) than his preferences and qualifications would predict.
So what I found myself doing while I was on the market, like many others, was applying more widely than I'd planned. Rather than only applying to schools in big cities, I'd apply to schools within an hour's drive of a city. Rather than looking in a particular region only, I'd suddenly find myself applying to a job halfway across the country, because the ad sounded like it was written for me and I probably stood a better chance of getting that job than a more general job ad.
So suddenly I found myself considering interview opportunities from a few schools - and absolutely none of them were in geographic locations I wanted to live in. And, you know, if the jobs had been absolutely perfect or I'd fallen in love with the towns, I'm sure I would have been happy.
But that wasn't the case. Instead, I found myself mulling over an offer from a job I didn't think I'd like, in a tiny little town in the middle of nowhere, far away from my family. And suddenly I realized how ridiculous it was for me to even consider the job.
Sure, I could be happy in an academic job if it was in a location I loved. But if where I lived was important to me, why would I consider taking an academic job in a location I'd hate ... when there would be a wide range of jobs I'd be qualified for with a masters' degree and Ph.D. in the locations I'd love to live in?
Geography may not matter to everyone. But if it matters to you, like it does to me, you will be better served to keep your options open. I'm not saying that you can't still consider academic jobs that are in geographic locations you'd like to live in (I plan to do this next season if I'm still looking for work). But if you think you wouldn't be happy working in academia absolutely anywhere, you really should keep your post-grad-school options open. Because despite what your advisors tell you, you have very little control over where you will live.