my two cents...
If you get a current consumer-grade flash memory camcorder - like those in the Canon HF M series, Firewire is irrelevant. Firewire is used only with miniDV tape based camcorders.
I have a 5 year old iMac running OSX (10.5.8) and FinalCut Express 4. I have successfully connected, imported and edited video from the Canon HF S100. When in Final Cut, under File, select Log and Capture. The camcorder needs to be in Play/PC mode.
I would not use a camcorder that captures high compression video for fast action - but that is just me. The only currently available low compression consumer-grade option that I know of is the Canon HV40 (miniDV tape based, requires the firewire port on your Mac).
Humans were not meant to be rock-steady. Use some sort of external stabilizer. Tripods are common. Helmet mount or shoulder mount are possible.
Camcorders with small lenses and imaging chip cannot behave well under low light. Large lenses and large imaging chips are required if video lighting is not possible.
If the built-in zoom is not enough, a "tele lens" can be added IF the camcorder has mounting threads. The "lens filter diameter" specification tells you if the threads are there.
A Network Attached Storage (NAS) device is another storage method. basically an array of hard drives. At the low end, 2 drives are mirrored - they have the same information (you only need to get the data onto on - software takes care of the copying. This is "RAID1". Chances that both drives will fail at the same time are slim. When one fails, replace it (hot-swap). The software copies the data from the good drive to the replacement.
Read through one or two of the camcorder/camera manuals. In there you will find a table that has the memory card size, various video quality selections and the amount of memory consumed. Always capture in highest quality.
There are adapters to mount an iPad to a tripod.
See the comment on lens diameter and imaging chip size regarding lighting condition video capture behavior. ANY video capture device can capture decent video if the lighting is adequate.