this is a rather common question that, based on my research, can be answered easily
1. if you want muscle gains (size and strength) then the one thing you will want to do is split your workout into a two day regimen. cardio in the morning is the correct way to do the first part - then eat about 30 mins after
2. come back later in the day (after meals and shit that will give you good energy) and hit the weights.
think of it like this - you wake up, you are on an empty stomach - you simply cannot get the same intensity of a workout as you could after a day of adding fuel (food) to your system.
if you are going to do cardio after a workout - a simply low intensity 20-30 min plan (bike) etc is good. remember, cardio to burn fat, and cardio to raise your heart rate beyond your fat burning rate are two totally dif. things. if you hit the weights hard enough (dont get sloppy..make sure to kick your ass with minimal rest between sets you will get a good cardio workout during your muscle routine.