Here's the dilemma. I get on well with the people I work with and it's a fairly easy going place to work. Is reducing my commute worth the risk of working somewhere I may not like as much? I have no reason to suspect the new place may not be as good, but I've previously worked for some truly horrible people and there's always that risk...
Finding a new job is such an unsatisfactory process. You meet a few people during the interview process, but not necessarily the people you'll work with. You get a well presented version of the place you'll be working, and get sugar coated answers to your questions. The first day can often be an eye opener!
The other temptation for moving is just to try something new. I've been at my current job for 8 and a half years and I've always had it in mind that 10 years is too long to spend anywhere. Not sure when I decided this, just looks like a long time written on a CV!
Of course this may all be decided for me, maybe they won't ask me for another interview!