Every day the technology gets better and more affordable , putting powerful and professional editing within your grasp. You can now have frame accurate editing, powerful visual effects, sound mixing, titling, blue-screening and CGI modelling all on your desktop. The key to all of this is non-linear computer editing. In traditional video editing you copy segments of your rushes tape to your master tape - laying shots in order linearly onto your tape. Get to the end of a sequence and decide that you want to change the 3rd shot and you have to edit the entire sequence all over again.
Film editing is non-linear.
Computer editing combines the best of both worlds - no need hunt through rooms of film to find your shot and its equally able to edit sequences together in any order. Any machine produced in the last couple of years should be pretty capable. Lots of RAM is nice - video applications tend to gobble it up. Having spare expansion slots such as a PCI slot is vital allowing you to add a video capture card. Likewise use a Firewire card for DV camcorders.