I enjoy going to the gym and when I'm in a good spot I'll go about 4 times a week. My problem is that I absolutely loath cardio, however I love weights. I definitely want to build muscle and get stronger but I hear time and time again if I want to lose weight (i.e. fat) I need to do cardio. Is that necessarily true? Is there anyone here that focuses solely on lifting weights? Right now on days that I do weights I do a 10 minute warm up on the treadmill or eliptical and then do my weights circuit.
Also can I do my whole circuit (upper body, lower body, core) each day? How heavy do you have to be lifting in order to need rest days for a muscle group?

Cardio just 2x a week. Though, like you I usually warm up with 10 minutes of cardio. It does help with fat burning. Have you tried doing HIIT (high intensity interval training)? It's a cardio workout where you do intervals of going all out followed by recovery at steady state. If you google it you'll find lots of info. It's better than just plodding along.

Lots of lifting to keep the weight lifter in you happy, constantly varied and challenging, which keeps it from getting boring, at least for me. Crossfit(dot)com is a good place to start, if you've never heard of it. Any of the workouts can be scaled down in reps/weight for beginners or modified to suit any physical or equipment limitations. If you hate the strict cardio days, check it out.
- works every time and you can't beat the calories burned.