Re: PSU - Which way is up?
Pretty much depends on where your air vents are on your case. As yami said, if you've got holes in the bottom of your case to allow for airflow to the PSU, put the PSU in with the fan facing downwards.
If not, as Apok said, face it towards the middle.
"As a result of all this hardship, dirt, thirst, and wombats, you would expect Australians to be a sour lot. Instead, they are genial, jolly, cheerful, and always willing to share a kind word with a stranger, unless they are an American." -- Douglas Adams