Yes, Garritan is good, but not fully automatized.
IMO, Old Yamaha XG Softsynth is still the best option for standard 128-instrument General Midi.
I just listened to couple of soundfonts mentioned here, none of them is good enough compared to Yamaha.
The key moment is BALANCE. Sure that every soundfont has "Excellent sounds". Yes, single instruments can sound realistically. But any COMBINATION of them involves calculation of individual chorus, reverb and many other parameters. The Yamaha still manages this task better than any soundfont, no matter how huge it is.
I'm very big fan of GM midi's since the 2000 year and Pentium era. Regularly I've been monitoring the web for new soundfonts, softsynths and other. The answer is no. Not a Roland, not a Native Instruments. The more instruments are involved - the clearer is the difference.