Apple ProRes also works fine. You need the drive and bus speed to handle it though.
Codecs can be important. Especially with PT that doesn't seem to like h264. But with Nuendo and other DAWs it works just fine.
H264 always needs to have key frames on each frame in QT language. Otherwise it won't be frame accurate, and it will look like shit when pressing play and until it has hit the first key frame. h264 also requires more CPU power when decompressing the film, so all these factors in total makes it into a less than desirable codec in most cases.
And when adding key frames to all frames, its not a very efficient codec compared to the other choices below and it will use a lot more CPU on playback.
H264 is a great preview and internet format though.
Apple ProRes has several sub codecs. It's 4444, 422(HQ), 422, LT and Proxy.
4444 is for really high quality and keeps alpha channels and color space at the highest level while still having a lower data rate compared to uncompressed.
422(HQ) is when you really need that great picture on a really big screen to impress clients or when you go to a dubstage, but don't need full color space or alpha channels.
422 is still great looking HD codec and we often use it in our dubstage as it is efficient and still looks pretty good.
LT looks quite good still and is a pretty good choice for Sound editing but won't really be good enough for the big screen of a dubstage.
Proxy is a lower quality output that most folks would accept for offline and sound editing, I don't really think it does though and although its at the same data rate as the Avid DNx36, it does not look as good.
Avoids DNx codec is pretty similar to ProRes. The codec names are formatted like DNXnn, where nn is the data rate.
DNx220 almost best.
DNx145 still great.
DNx36 pretty darn good considering its low data rate. Can even be used on a dubstage with decent quality, but artefacts will be visible.
In my opinion since there are the above choices of great codecs there really is no reason to use anything else really. If your machines can't handle ProRes Proxy or DNx36, you really should get a new machine.
Also a good advice is to always stay at standard resolutions.
SD 720x576 in Pal, 720x486 in NTSC.
HD 1280x720, 1920x1080.
Doing this means that the signals can use standard video transmission systems and interconnections without needing to be realtime converted at the output, if its even possible (dependant on what card is used).