This is my current fan layout http://i.imgur.com/ERTrCol.jpg
Is it better if I flipped the direction of a few fans or is having almost all of them pointing in the same direction most efficient?
Make the front fans an intake for the GPU and CPU. Flip the PSU so that it's not taking air away from the GPU and CPU. Make the rear fan your exhaust, and if you have an extra fan add it to the top as an additional exhaust. It's efficient that way since hot air naturally rises and your components aren't recycling used air.
I think he's already taking are in from the front and exhausting through the back, exept for the PSU.
Yeah, I think i mistook his arrows for airflow.
You can also install an additional intake fan on the side.
If I added another fan to the heat sync wouldn't one fan be blowing into the other, which is pointless?
its a tad bit better ... price vs performance is pointless .. but you can run your fans slower with better cooling so your pc would be quieter .. if you do add another i would get a fan power splitter so both fans are always running at the same rpm
You can freely choose the direction when mounting the fan. Of course, you want them to blow in the same direction (as in, help each other, not cancel).