Win 7 64bit: To use all 64 bit apps or not? That is the question

I have a windows 7 64 bit OS. Hardware - all the bits and pieces on the motherboard, will be faster and better optimized in 64bit of course they all use 64 bit drivers but what about general software? Should one fill the system with 64 bit apps, choosing only those apps for 64 bit over 32 bit?

The argument goes like this, most 32 bit apps will work fine in a 64bit OS but they will not be as fast or efficient because they are only using about half the volume of space inside the connections inside the pc they use to travel through. It's like the difference between a 1 inch hose (32 bit) and a 2 inch hose (64 bit). If you only put the same volume of water through the 2 inch hose as you would for the 1 inch hose you are not going to be as efficient. Using the 2 inch hose will be double the volume, thus making it more efficient and faster. Many people say this old analogy is a bit off and not entirely correct.

32 bit software does use a little less memory (ram) than 64 bit but not a lot more, just a tiny bit. Still this is more. It can be argued the more 64 bit programs you run the less memory is available to run more apps. If you use all 32 bit apps you will have more ram left over for more programs to run.

Does using all 64 bit apps in a 64 bit machine make it run faster and more efficient overall? Whats the official word on the trade off, whats the pros and cons I'm missing?

Just like 16 to 32 bit I'm sure the day will come when 32 bit apps are no longer made and we will have to use all 64 bit apps, still I want to know your thoughts on these things so I can make the best choice for me today.

I have actually found very little I cannot do in a 64 bit app. Sure perhaps some popular apps don't have a 64 bit version yet, but if you look hard enough, most things you want to do will have a 64 bit version somewhere, and growing everyday. I assure you I can easily fill my drive with all 64 bit apps for anything I could think of. 3 years ago I would have agreed with you about it being a moot point but the time is here now for it to be reality.