I have had good results with the Dawson Precision adjustable sight set from CPWSA (http://www.cpwsa.com/Dawson_Precision.htm). Scroll down the page and you'll see the set. I use these on a Glock G34. I found the narrow front sight post to be very helpful in helping me get a good sight picture quickly as I move from target to target in USPSA.
Whatever you get, be SURE to buy sights in complete sets (front and rear) for a specific gun.