I feel the best training program is a combination of periodized and high-intensity programs. So far this type of program has produced the best results for me. Some of the added benifits of this type of program is that you aren't spending every day in the gym and when you do go you can be done with you weightlifting in under an hour.

The philosophy behind the program is that you want to steadily put more stress on you muscles and use hight and low rep ranges to increase strength as well as muscle size and that you often need to back-off on your training to avoid hitting plateaus.

Before starting this program you may want to take a week off to allow your body to recouperate from your current training program.

Here's the basic plan:

On regular work weeks there are always 3 half-body workout sessions per week.

Microcycle 1: Weeks 1-3
This cycle is to get you ready for the intense workouts to come later. These long sets can be really painfull, and very productive.

High Reps, Light Weight Workout A: Leg Press, Leg Extension, Leg Curl, Seated Calf Raise, Seated DB Press, Side DB Raise, Shrugs, Back Extensions
Workout B: DB Bench Press, Incline DB Press, Overhead Tricep DB Extnsion, Parallel Grip Lat Pulldown, Wide Grip Lat Pulldown, Seated DB Curl, Cable Curl, Crunches

Microcycle 2: Week 4 (Rest)
This cycle is intended to give you some rest. If done properly the last few weeks have been really stressful. You should also use this weeks workouts to determine the weights for the next cycle. There are only two workouts this "week" (it's actually longer than a week). You should skip you next workout, then continue where you left off with the next two, and then skip the next week also. Use the same exercises as you did in the prevoius cycle.

Microcycle 3: Weeks 5-7
This is when we really start to increase the intensity. Once you reach the upper rep range you can add reps with long negatives. It is important that you don't increase the weights used on exercises before you are really able to do more in good form. If you do it will cause your progress to slow. You should see real strength increases each workout. One problem I encountered during this cycle is that the min and max repitions are fairly close together. On DB exercises the minimum weight increase is usually 5 pounds. This may be too much. You have to play this by ear and decide for your self what to do if you find yourself in this situation. Continue to use the same exercises.

Microcycle 4: Week 8 (Rest)
Another rest week. Skip one workout, do the next and then skip another. This rest week is important because from now on you will be using really heavy weights and you don't want to burn out during any of these cycles. Use this rest week to determine the weights you want should be using for the next microcycle. Continue with the same exercises.

Microcycle 5: Weeks 9-11
During this cycle you will be doing full-body workouts as opposed to the half-body workouts that were used in the prevoius cycles. You should also cut out the isolation exercises in the workout routine and just do the compuund movements. So, you will still be doing the same total ammount of work, but it is just split-up differently. You should now be using heavier weights, so make sure you don't sacrifice form or use a weight that is too heavy. Drop isolation exercises from routine and continue with compound exercises.

Microcycle 6: Weeks 12 (Rest)
Really rest week this week. Use thsi week to determine the weights for the next cycle. Skip one workout, do the next, then skip one again. Continue with same exercises from the previous cycle.

Microcycle 7: Week 13-15
This is the last work microcycle of this macrocycle. Really push your self to the limit. Remember to add negatives and static contractions when possible, but don't go beyond your limits. You should be using really heavy weights now. Continue with same exercises from the previous cycle.

Microcycle 8: Week 16 (Rest)
Take this week completely off. No lifting for 7 days.
When you begin the cycle again you can start with the first of second microcycle. If you  have been eating well then you should have had a decent increase in weight and strength. From my experience it is possible to gain weight and strength while losing fat while on this program. See my page on diet and nutrition for more information.