As this is my favorite system of all-time I gave it the 10. The 7800 was actually my first system, but thanks the backwards compatibility I bought 2600 games concurrently with 7800 and NES games through the late '80s and even into the early '90s when I added a Lynx and a Genesis.
It has plenty of games I consider top notch. Like others have said the paddle controllers are great, but I am not a Kaboom! fan. My favorite paddle games include Breakout, Video Olympics, Warlords, Super Breakout, Tac-Scan, and Circus Atari. Indy 500 with the driving controller is also great.
Some of my favorite joystick games are Pitfall!, Pitfall II: Lost Caverns, Combat, Air-Sea Battle, Montezuma's Revenge, Q*bert, Frogger, Omega Race, Spy Hunter, Wizard of Wor, Atlantis, Star Raiders, Starmaster, Star Voyager, and well this list goes on and on.
An easy perfect 10 for me.
Also has the best Superman game ever made.