In her book Strong Women Stay Slim, Miriam Nelson, a Tufts University researcher, showed that a group of women who followed a weight loss diet and did weight training exercises lost 44% more fat than those who only followed the diet. While aerobic activity can help burn calories, muscle's where it's at when it comes to giving your metabolism a significant daily boost even at rest.
A lot of cardio work, particularly of the endurance-based variety (e.g. distance running), will inhibit your maximal strength gains and ability to put on muscle mass. In other words, if your goal is to max out on the squat or bench press, or to get super huge, keep the long distance running to a minimum.
When done in the same workout, put strength training first. The body uses fuels in a particular order of preference. If you put a lot of cardio in before you do strength training, you’ll run out of gas.
If you’re just looking for general fitness, one no-brainer way to organize things is just to alternate weight training and cardio days. This gives you daily activity but mixes things up so you’re fresh.
