If you've done nothing in the last 10 years, then you're definately overthinking this.
After 10 years of relative inactivity, I'd just get my ass in the gym for 40 min of weights one day, and 20 min of cardio (increasing over time) the next. First week start LIGHT!!, second week add a bit more and get to a MEDIUM level for a month.
After 10 years use machines or lighter free weights to condition your body again. It will take a month or so but if you fail to do this, likely you're asking for injury. All the young guys on this board are going to call "bull shit, it never happened to me!" but I assume after a decade of inactivity, you're a little older and you DO need this conditioning. It will increase your metabolism and combined with diet it will begin weight loss and improve your physical condition.
When your body starts to feel ready (after a month or so of this) then start increasing your weights to substantial "straining lifts". I would suggest reading the 5X5 training sticky and lots of diet stuff for training.
Really, it's not rocket science. Get some excersise to get into the "groove" then move on to a more "bodybuilding" type of routine (if that's what your after).
I spent a good 6 years out of the gym and turning into a couch tumour before I got back into it. I can tell you with absolute certainty that the first 2 months were critical in getting my joints, cartlidge, connective tissues, and muscles used to the kind of strain I was going to be putting on them. I moved to a 5X5 routine and can now bench over 300lbs (265 for reps). I've been where you are. For the next month or two JUST GET TO THE GYM 6 days a week! OK?
Not only just conditioning your body, but your life too! You will notice that most of the folks on this board will sacrifice a part of their day for the gym/excersise almost no matter what. I will book off work if I have to. Be late for stuff. Whatever it takes! If you make this commitment and let your family know this as well, you'd be surprised how much support you might get. "Sorry I HAVE to go to the gym" should be a phrase to add to your daily vocabulary....get it?
And stop reading those stupid Men's Health magazines. THEY SUCK! They are just red herrings.
One more thing. GOOD LUCK TO YOU!
And stay on this board, good info and the folks here are generally quite supportive!
edit: If you are one of those guys who absolutely need a program to follow, then as a beginner routine/program. I'd simply suggest the Body For Life program. It's got some failings and the author is a bit of a hypocrite and a weenie, but just to get you going it's not bad. I will still even cruise on the program for a couple of weeks sometimes just cause it's easy to follow and you need breaks from eye-popping heavy lifting ever few months. Further, I followed it for a while and never recorded a thing (if I have to actually write something on paper in the gym, I'll lose interest - 5X5 is like that for me too - all kept in the huge empty space in my head...lol!)