“Ok, let’s start with cardio goals. The reason I do such low impact / low intensity cardio workouts is that I want to burn some fat and give my heart a little exercise…nothing more. Is my thinking wrong?”
No, your not wrong and it that is your goals then working out in the so-called "fat burning zone" will be ok. If you really want to burn some calories, then you need to crank up the intensity. I prefer Fartlek training where you adjust the intensity up and down as you go, but don't stop. (Read the current Cardio is Anabolic Post or the Sprinting for fat loss thread (they are both still active) for more info or I can bump up an old post where I discussed aerobic intensity and its relation to fuel mixture (carb/fat) burning, but it gets a little intense.)
"I tried to find the Mufasa article that you spoke about, but the search engine on the left isn't working. I looked up "Mufasa" and got a user-defined error."
Yeah, the search engine is up and down here, but just scroll down to page 3 or 4 for the post titled Jason N:BF% Follow Up.
"The 5x5 approach definitely interests me. After 12 weeks of 10 rep sets, I'm ready for a change. Just so I'm clear, though, are you recommending I start this program now?"
"I thought the whole point of the two-week "recovery" training was to take it easier on the body and to get it ready for the next wave of attack. Again, if I'm wrong, let me know."
No, you are right, but by doing a 5x5 based program, you will be significantly cutting volume while providing a stimulus to maintain muscle mass and increase strength. Believe me, you will be taking it easier than a high volume hypetrophy based workout.
"Also, along this same subject line, don't you think strength training and bodybuilding are different? In other words, the bodybuilder may not be the strongest of the lot, but clearly he or she looks the best. That's really my goal. I don't care as much about being powerfully strong as I do LOOKING powerfully strong."
Yes, they are different, but both athletes need to use each other's primary training techniques from time to time. There comes a period in a bodybuilder's life when they have to become stronger before they can become bigger and there comes a time in a powerlifters life when they have to become bigger to get stronger.
"I'm a little nervous that the 5x5 program will give me huge strength gains but significantly less mass gains than I would have if I used the approach I had been using."
If all the work that you have been doing is 10+ reps, then you may be shocked to see that lower reps still cause significant hypertrophy and strength gains.
"As far as diet, I'm taking your advice. I'll work my calories down to 3500 per day, reducing it steadily over the course of this week. I'll keep the composition of food at 33/33/33 (or thereabouts!), and keep my protein intake at about 300g."
Very good! What are your goals for the future? How long do you plan to cycle 2on/2off with MAG-10?
BTW, as of when I wrote this, all the posts I referred to by title were active on the training/nutrition board, but they could be on page 1,2,3 or 4 so look around a bit.