I'm not a film editor, but I speak from a little bit of experience first with a SD Sony MiniDV Handycam, then a SD Sanyo MiniDV Cam and now a Sony SR5 Hard Drive High Def Cam.
System Requirements: First and foremost, yes, 2GB is the absolute minimum to edit. I used to use 1GB and an SD clip of under an hour would take 8-9 hours overnight while seemingly freezing up your computer. I have no experience with MAC, if you plan on serious video editing I suggest you look into this option. Currently I'm using a Dell Vostro 1700 3GB Ram and have internal/external hard drives of over 2 terabytes. It is essential to have enough hard drive space. You probably want to edit from a HD on your computer so you aren't limited by USB transfer speeds so I suggest at least 30-50 gigs of free space depending on then number and size of video editing projects you plan on working on.
This will require a time investment: Minimally plan on spending an entire afternoon or evenings (about 6 hours) learning the software, downloading codecs, making sure videos plan in the right player, learning editing options and waiting while your computer does the transfer/edit process. If you are only trying to edit a small clip for your personal amusement once and done, I would suggest forget about video editing. That said, once you learn how to use the software it?s pretty easy. I come back after recording, pull the video off my camera, edit out a few frames, add some titles and maybe a background soundtrack then let my computer do the rest.
Are you editing SD or HD formats? Just about every software package out there has mastered SD video editing by now. So you really want to look at the features and 'extras' offered by each program. I used Pinnacle Studio in the past with lots of luck.
Video Formats: Each software offers a variety of video compression formats. Personally, I prefer formats viewable on my computer that are compatible with my HD files. You may want to make sure that files burn to DVDs for home use or backup. Do not rely on DVDs to backup your data forever. They can/will scratch easily and all of your memories will be lost. Do NOT count on Hard Drives to backup all of your data, they can and will break. I backup all of my pictures monthly onto an offsite DVD and all of my video is stored on three separate hard drives one of which is my laptop for offsite storage (in the event of a fire). If you haven't lost data yet feel very fortunate and realize your time is approaching.
HD Hell: Early adaptation of technology has its frustrations. Just a few months ago HD formats were more than troublesome to edit and not all (read: most) software packages knew how to tango with the new HD quality. A few months ago I would have said wait, but the time is approaching for HD (although I would still wait just a few months for 2008 models). HD editing is more commonplace and a variety of formats exist depending upon your manufacturer. Make sure you know what kind of HD format your manufacturer uses and then research and make sure the software supports it.
Again, I use Pinnacle Studio 11 Ultimate (its worth all the features) and they have recently alleviated all my HD headaches by handling most all HD formats.
Encoding: Video software can encode in NUMEROUS formats so understand each and play around with each. I backup one high def version for viewing at home and one compressed format for sharing, sending and posting. Find out which format works and looks best to you. With HD you must have an HD capable video player. I my learning phase I THOUGHT I had encoded HD video and was watching it unimpressed only to find out that my player did not support HD viewing. I currently use Nero Showtime and PowerDVD7 to view HD videos.
Sorry this is on the long winded side, if there's anything I can clarify or help you further with please don't hesitate to ask.
-EK