Audio

I'm not going to go into the world of microphones as I don't have the time or I feel the expertise. 

The one microphone I will recommend though is the Rode Videomic. Cheap and great for run and gun shooting, but only worth getting with the 5D.

For anyone who doesn't have a 5D or just those who want the best audio on a budget the Zoom H4n is a great option. It has onboard stereo mics that work very well when coupled with a windshield (you have to get one separately from a company in Hawaii).

The reason the H4n is so commonly used by DSLR film makers however is because it features two XLR inputs on the bottom. They supply phantom power meaning you can use any mic you please. You can record 24bit audio at up to 96khz and up to 4 channels. There is also a 3.5mm input for smaller mics.

I do find it a little slow to boot up which is an irritation, and it is a little bulkier than most pictures make it seem. Also if you are running mics on phantom power expect to go through a lot of AA batteries. My only other complain is I find out of the box it is a little 'boomy' however it features a low cut filter on the device which means you can solve this pretty much straight away.

For those wanting a more basic audio setup it might be worth waiting for the Zoom H1 otherwise I've found the H4n completely invaluable.