Well there really shouldn't be any question.
You can't take pictures without a camera, you can't take video without a camera, you can't take pictures or video with a nice computer. So if you want to take pictures or video, get a camera!
Any computer can do basic cropping and maybe even red eye, and spot touchup, a little saturation and such, but you need pictures in the first place.
As for video editing, about 2 years ago I edited a 15 minute DVD resolution snowboard film using Corel Video studio for XP on an old Celeron M notebook with 512 MB of RAM and I'm not even sure if graphics existed back when that thing was made, must have been 5 years old at the time.
So even if you don't have a cutting edge system right now, you can still use it as an outlet for your creativity, but you need material first.