What codecs should I use?
On the video side, this depends on how onerous you find the H.264 patent licensing terms. Frankly, they’re pretty liberal at the moment, so H.264 works for most people. It’s the best quality codec around and the most widely deployed, so it’s a good default. Again, be sure to understand the licensing terms.
Try VP8 if you want a new, emerging codec that is totally free and unencumbered by patents. Try Theora if you want a more established free codec, and can live with a bit less compressibility. But keep in mind that neither Theora nor VP8 are playable in every browser, whereas H.264 is playable in 99.9% of browsers.