I lol at those who argue about 1x or 2x per body part

Not all bodyparts are equal.

For instance, shoulders, while a major body part, is obviously smaller than the chest or the back.

Here is what the training frequency should be like:
Shoulders 1x a week
Legs 2x a week
Back 2x a week
Chest 2x a week (however, the second session should be planned carefully as many chest exercises will involve the delts)
Arms 1x a week

Abs and calves are a little more up to personal discretion.

Why you shouldn't be concerned if your weight is dropping despite trying to "bulk" up

Disclaimer:  This article isn't for fatties.  Obviously.

When one goes to the gym, one is usually in pursuit of one of these three goals: aesthetics, to develop the body for sports (general), or strength training (leisure or competitive).  None of which, should be based on the weighing scale.

If one is going for aesthetics, his concern should be on how he looks.  Bruce Lee's highest weight was 165lbs/73kg, but I would dare to say he would look better than most people who weigh in at 180lbs.  Frank Zane (see below) beat Arnold to the Mr.Olympia title despite being some 40lbs lighter.  He continued to win three straight Mr Olympia titles despite being under 200lbs/90kg.  Aesthetics is a subjective matter.  If people are coming to you and giving you compliments, then whatever you are doing is working, be it the weighing scale telling you that you have gone up in weight or not.  The only relevant objective measurement one can make in the pursuit of such a subjective goal, is the measuring tape.

If one is in the gym in order to become stronger and faster so as to enhance his performance in his sport, then it really doesn't matter how much he weighs, if he is doing better on the field/court.  In such cases, the main goal is performance on the field/court, not the gym, or how much the bathroom scale moves.  Never be detracted from your actual goal.

If one is in pursuit of strength, then it doesn't matter how much he weighs if his lifts are going up.  In fact, it is obviously more impressive if one can lift the same weight at a lighter bodyweight.  And this also bodes well for those who compete-lower weight class but higher lifts equal a better chance to win.

So don't be overly concerned by how much you weigh.  Remember, the reason why you're in the gym is not because you want to change your weight!

Why you should do push-ups

Most people brush off this exercise, either claiming it to be too easy and/or just something gym teachers use to punish pesky kids.  But the push-up can be just the exercise to push you a step closer to the chest you desire.

Are you too good for the push-up?

Are you really too good for the push-up?  Chances are, no.

The US Army physical fitness test is made up of sit-ups, a two-mile run and you guessed it, push-ups.

If the US Army isn't good enough for you, try Jim Wendler.   For those who don't know Jim Wendler, I would just sum it up for you-he is a kickass elite powerlifter.  Jim Wendler himself recommends push-ups to get stronger at the bench press here and here's a picture of the man himself doing push-ups.

But I can do plenty of push-ups and high reps are just endurance!

I know there will be plenty of you who would be screaming that with push-ups, we will end up doing in the high reps region. 

First of all, you can do weighted push-ups to bring down the rep scheme.

Secondly and more importantly, don't discount high rep work  The old-school 20 rep squats program, which is held in high regard, is in the region of 20 reps.  What about Kroc rows?  To paraphrase Wendler, you can be considered to have become stronger if you are able to do more reps of the same weight.

How about some Maths?

While being able to bench your bodyweight is nothing to brag about, it is still a fair indication that one is no longer an untrained weakling.  Now, a push-up provides 50-70% of your bodyweight as resistance.  Taking the midpoint of 60% and assuming your 1RM=your bodyweight, it means you would be using a 60% load.  If you're a fairly discerning lifter, you would know you should be able to lift this load in the region of 10-20 reps, which is exactly how many push-ups you would probably be knocking out if you're doing this at the end of your chest workout.

Hold on a minute you say, I bench more than my bodyweight.  So I do, but that's still cool, because I'm not suggesting you put the push-ups at the start of your workout.  You do them at the end of your workout when fatigue is setting in and the poundages are starting to go down. 

How about a real-life example?

You can read about one here.

What exactly is my point?

I'm still undecided on using push-ups as an emphasis in a routine (unless you have specific goals such as a test).  However, push-ups are definitely very valuable exercises that can help you achieve the chest you want.

Note:  By push-ups, I meant push-ups with a medium-width hand position, not those with your arms at the side of your body.  Those do not give your chest a proper workout.