Enigma is an AMD fanatic. Pay no attention to his garbage. If you're curious what he's talking about though, the AMD quads and the Intel Core i7 are quad cores with all 4 cores on a single processor die. However, the Intel Core 2 Quads are instead a pair of dual core dies, hooked together within the CPU. This configuration with 2 dual core dies is referred to as a multi chip module. They perform great, and have no significant performance disadvantages as they are implemented right now.
Between those two, the Q9300 will perform slightly better at a given clock speed, and run cooler with less power. However, the 6600 could perhaps give a slightly higher absolute overclock. For 3.2GHz or so, I'd just go with the 9300, as it will easily hit that and run cooler.