Here's David Tames' kino-eye.com: Secret recipe for amazing image quality video downloads.
He prefers H.264.
I prefer mp4, since H.264 requires QuickTime 7 and runs slow on my old 667Mhz Powerbook.
But you can follow his guidelines and still use .mp4 instead of H.264 inside the .mov wrapper.
This means that you export a Quicktime movie, but use either the H.264 or .mp4 codec. So you end up with a .mov movie.
Here are my settings:
EXPORT
Movie to QuickTime Movie
VIDEO OPTIONS
SETTINGS
Compression Type: MPEG-4 Video
Frame Rate: 15 fps
Key Frames: Every 24 Frames
Quality: Move slider just to the right of MEDIUM. [ Thanks Alex Lindsey ]
PRESS [OPTION] to display Temporal: Move slider just to the right of MEDIUM. [ Thanks Alex Lindsey ]
Date Rate: Restrict to 500 kbits/sec [ Optionaly try 300 or Automatic ]
SIZE: Width 320 Height: 240
SOUND
Format: AAC
Sample Rate: 32.00
Channels: Mono
Bit Rate: 48 kbps
PREPARE FOR INTERNET STREAMING
Fast Start