Is it OK to leave my PC on all the time?

It won't present a problem if the computer is in good working order. It's only an issue if it has preexisting conditions such as overheating. It will shorten the life expectancy of some components, but extend others. For example, the fans will need to be oiled sooner, but the hard drive won't need to spin up as often. However all that is fairly moot since you likely will only own the computer 2-5 years, which should still be an expected range for the components.

Electricity consumption is a major issue though. I suggest you keep it in standby.

It also depends on what is running on your computer. There are lot of poorly written web-aps that leave memory leaks on the computer. If you run too many of these, it will start to bog the computer down with un-released memory. A restart would clear that up.

It's a minor issue, but sometimes still an issue.

You can do whatever makes you happy. Turning the computer off saves energy. The effect on the computer's life is debatable. The general consensus is that if you're not going to use your computer for at least four hours, it's best to shut it off. But unless there's something wrong with it (for example, if it's overheating), there's no harm in leaving it on.

I agree with CTN, leaving it on all the time could be bad if you have bad cooling systems, but turning it on and off a lot can also harm the laptop too. I would leave it on, but dont have it running anything, just have it asleep or in idle so its in a low power state.

there has been a lot of controversy over this question, some say its better to power it down due to power consumption and heat shortens the life span, but i say leave it on because it reduces wear and tear on your hard drive. If you don't mind the power bill, there is nothing wrong with leaving it on.

it is better to leave it on rather than shutting it down every hour or two.however, your OS too needs some rest, to prevent it from crashing,so try shutting it down every six or seven hours. and do watch out from your electric bills!

no that is not a good idea at all!! if you leave your computer on to long then you are going to loose all of tour work very quickly the side effects will be, your computer will suddenlt start slowing down and then your computer will start freezing so i suggest that you dont leave your computer on:)

If you have good air circulation, then yer it is fine.