OK - A bit more time available today. Here are my thoughts. I am age 40, and at one point in time I focused soley on Body building with no cardio. My friend was more like you. Tall and lanky with a focus mostly on cardio and none on body building.
There are two main goals that people are seeking when they lift weights. One to add bulk, then other to tone. These are mainly accomplised by changing your weight to repatition ratios. Lower Reps with heavier weights to add bulk, higher Reps with lower weights to tone. You can do whichever suits your needs. If you feel you want to add some #'s, then you can start off with bulk and change to tone later. (either way there is a side benefit to lifting weights for those focused on cardio, and that is that it will strengthen your body and help to prevent injury.)
For bulk your sets should be in the 10 - 6 range. the weight should be such that you can not accomplish the 10 - 6 with out a spotters help. If you do not have a spotter, then you will have to go as heavy as you are comfortable with.
For tone your sets should be in the 18 - 10 range.
Form is very important to prevent injury and not cheat yourself. For instance on bench press, you should lower the weight slowly, then push the weight up. Do not bounce off your chest. This will also give you a better workout.
You mention being more balanced. I am a big believer in balance. You probably put "upper body" because you feel the cardio works your lower body, and this is true to a point. However, you should also add some strenght training to your lower body as well. When I hit the ceiling on my upper body, adding lower helped be get beyond and break through with my upper body.
When I was serious, 6 days on and one day off was my routine. I worked on 3 different focuses on two different days. So, lower body, Upper body Core, and smaller muscles. Then I would start over. If you do not have that much time, like when I got a job, then I would lower it to about 4 times per week. 2 days on, 1 day off, 2 days on, 2 days off.
Here is a routine:
Day one: Upper body - - I like to not take breaks and work in a protaganistic movement with an antagnaistic movement. This helps me to finish faster and keep my heart rate up during exercise.
* Bench Press Flat with seated close grip rows. Do one set of warm up, then 3 sets of increasing weight. Your reps should be in line with the before mentioned goals. You alternate between them. Bench, Seated rows, bench, seated rows. No rest between.
* Bench flys with bent over flys. These are done with dumbells and should feel very good stretching the muscle on the way down and flexing on the way up.
* Behind the neck seated shoulder press with wide grip pull downs.
* Pullovers.
(This would be the end if I was on the 6 day per week - You can combine more exercises to lift weights on less days)
Day #2 - Small muscle groups.
* Bicept curls with tricept press downs. I used straight bars for both of these.
* More bicepts with tricepts - This time using dumbells for the bicepts and a rope (or dumbells) for the tricepts.
* Upright rows with shoulder shrugs.
* Lastly I would work on my abs this day for strength. (I would often do crunches at the end of the daily workouts, but this way would be weighted.)
Day #3 - LOWER BODY
* squats (Or leg press, but squats are better) with calf raises. My calf raises would alternate toe position to work different areas of the calf.
* Leg extentions and leg curls.
* lunges
* I would often add an exercise I call "butt ups" I do not know the technical name, but you lie on your back, bend your knees until your feet are next to your rear, then lift you hips off the floor squeezing the glutes each time.
at any age, but more importantly as you get older, you should work in stretching before, between and after these exercises. With out it you can loose mobility. Yoga is a great complimentary exercise with weight lifting.
Sorry to type so much, but I hope that this helps get you going. Let me know if you need any assistance on how to do the exercise above as I know that the same exercise is often known by different names accross the country.
Best of luck,
Jim C#2