I vote glock 17. Both are great guns, and neither will disappoint. I own an m9 (essentially identical to the 92) a glock 19 - just slightly smaller than the 17. You should look into the g19 too - the slightly shorter slide makes it more pleasant to handle, IMO, without comprimising much.
Both the glock and the beretta are extremely reliable. The glock may have a slight edge in longevity. The glock has a factory option of night sights (which I HIGHLY recommend - even if you don't need the capability, the night sights are steel while the standard are plastic). The Beretta, AFAIK, does not have a night sights option. Put the savings of the glock into the sights.
The 92 is usually a DA/SA (though there are double action only versions). I'm OK with the DA/SA trigger, but some don't like the heavy first trigger pull. It is quite different from the subsequent pulls. THe glock has the same pull each time, and it's pretty light (it's pre set, as compared to a Sig DAO trigger)
The main reason I like the glock -- the controls. No safeties, decocking levers, etc. I don't even mind the presence of the controls on the Beretta - I don't like their location. I find that when racking the slide under stress, in malfunction clearance, reloads, etc., the hand often hits the controls on the Beretta, engaging the safety accidentally (or else, hurting the hand). Then you go to take the next shot and - surprise. Manipulating the slide from the front is inconvienient because it gets very hot!
Anyway..just my 2 cents. Both are great guns. The best option, of course, is try to get some trigger time on both. Let us know how you make out!!