I will second Chris in recommending the G17 for production, that is what I use. A great gun, should be under $500 new, absolutely fantastic quality magazines are less than $20 each, aftermarket support for sights and so on is probably the most extensive out there. You won't have ANY problems finding a holster that suits you and your budget, you won't have any trouble finding spare parts. You won't have any trouble finding someone to work on it if you should ever have problems. They are very friendly to shoot, accurate too. Not to forget that you will look long and hard to find a more reliable gun.
There is a LOT going for Glocks, TONS more than goes against them.
Second on my list would be a G34.
I wouldn't recommend the PX4, not yet anyway. Support for them is next to zero if not zero. As they become more popular the support will come, then it will be much more in the running.
I really like shooting the CZ's and Beretta 92 style guns, but the long trigger reach for the first shot is really a bother for me with my small hands.