What we should really be asking ourselves is what it is that we need. What purpose will it serve? Once you know the purpose, ask yourself if there are any preferences you already have? Do you have a preference in grip length or width? Do you have a preference in action type, like SA, DA/SA, DAO, striker fired DAO, etc? Do those preferences match up with the intended use of the gun?
I think comments like this would be very helpful... for example, I have a WWII Hi-Power which gives me hammer bite pretty bad so I bought the PX4 and, after shooting it a while, decided I hated the slide mounted safety plus it sort of pointed to the right when I picked it up (I never understood what it meant that a gun 'naturally points'); then I bought an FNX-9 and, after shooting it a while, realized the safety would rub my thumb and I don't like how my finger rubs the trigger.
What gotcha's have other people experienced that told them the gun they purchased wasn't right for them?