1. 1911
Single stack, double stack, competition or defense, it doesn't matter. You can mold it to fit your needs, and when given the respect it demands, it will become an extension of your body and allow you to deliver fast and accurate rounds on target better than any other platform.
2. Glock
"Perfection", nothing is perfect, but the Glock comes pretty close as a service pistol imo. There is something to be said about simplicity, and the Glock led the way in the simple service pistol design imo. Load, point, and press. Low maintenance and light weight due to the use of polymer, and about as simple to use as an automatic pistol can be. Rugged, reliable, easy to operate, and low cost, it is no surprise that the Glock became so popular with LEO's and the public alike.
3 & 4. Springer XD and the Smith M&P series
Both have taken the Glock to a whole new level imo. Simple, low cost, and with better ergonomics. Excellent firearms for service and civilian use alike. Time will tell if they can unseat the Glock as the top polymer king.
5. CZ 75
THE excellent full metal full sized 9mm that feels more like a compact. The CZ improves on the BHP by adding double action capabilities, and an easier to manipulate thumb safety. The CZ is a well crafted and sturdy 9mm that can serve as either a service or defensive pistol with ease.