Well it looks like your set on editing but as for capturing if your going to use a mac then I would suggesting checking out
halo3forum.com, theres a thread there with tons of capture cards which you can look through and pick based on your computer..
If your going to capture on your PC you got two options depending on if its a desktop or laptop. If you have a desktop I suggest an internal capture card.. I'm sure most people would recommend an ATI Wonder Pro, which can be found on Ebay for around $100. If you get an ATI capture with VirtualDub, theres tons of quality tuts out there for virtual dub which get awesome quality.
If your looking for an external capture card, I suggest checking out the Dazzles, simple set up and easy use, however there is a small quality difference because you capture with the Studio 10, or 11 software which is included with the capture card.. This is what I have used in the past and the quality is good enough imo.
Pinnacle Dazzle DVD Video Creator Platinum
Um. I think thats all you need to know.. Oh if your gonna use virtual dub its free at
download.com