And I have just a couple of quick questions.

1) Can any problems be caused by routinely shutting down my PC after every gaming session? There's a lot of expensive equipment in there, and I don't want it to keep running when I'm not using it. I feel like shutting down the system should help with the longevity of the machine, but I may be wrong.

2) In the same vein as the first question, is it okay to shut off the power supply and then un-plug it from the wall after every shutdown? I'm basically trying to eliminate all power usage from this machine when it's not in use.

Will doing this help or hurt my machine?

The only difference it will make is maybe slightly reduce your electric bill. Computers are meant to be run all the time, as long as the components are not overheating, which they absolutely should not even be within the range of when you aren't using the computer, it's not a problem. You will do nothing to extend the life of your machine by doing this, but it won't cause any harm either other then maybe slight inconvenience for you. That being said it's a good idea to restart at-least once a week or so to clear old session data.

Personally I shut down my PC every night before I go to sleep and turn it on when I wake up in the morning as my gaming PC is also my everything-else PC.

Although it wouldn't surprise me if turning it on would actually decrease the lifespan of a computer as I'd imagine that startup would be one of the more stressful things that a computer does, like a car engine.

I have no idea if the start-up is stressful for the computer so you might be right about that, but I fail to see why you would think it's stressful for a car engine..

I run my PC 24/7 at 100% load (Folding@Home) and have never had a problem. My laptop gets shut off as soon as I'm done with it every time I use it. Neither use pattern is likely to have an impact on the computers within a normal upgrade cycle.

I'm not entirely sure on the details, but I once read that startup is hard on an engine simply because it needs to work harder than normal to get up to temp. But then that may just affect fuel consumption.

Although I'd guess that shutting a PC off and turning it on wouldn't have much of an impact either way, to the point that there's absolutely no reason not to leave it on all the time unless it's over-heating.

The quick heating and cooling of components every time you start up and shut down isn't that great for the system. It's best to just leave the system on at idle when you're not using it. It should idle with little power usage.

Also, the most stressful time for a hard drive is when you start up and it has to go from 0 to 7200RPM really quickly. Over the long run it may reduce the life of the HDD.

It's not capable of working harder to gain temp, start-up just adds wear and tear to the starter and consumes a drop in the bucket more fuel then normal use, that's it.

Standing objects don't like to be put into motion so it goes to reason that you'd cause extra wear and tear on an engine that is both cold and still.

Engine components aren't made out of plastic you know...a set of forged rods or crank or any valvetrain component isn't going to be effected at all by being stopped and started again. The wear and tear comes from running at high RPM's, running into detonation, running a radical camshaft, etc.