I want to do some video editing and DVD encoding, and am trying to decide between the C2Q and the newer i3, i5 CPUs. I currently have a C2D, but haven't tried any DVD encoding with it. Maybe it would be fine?
You can encode on any CPU, only it takes longer on a dual core. Try it. If you get the i3 or i5 you need to change the motherboard/RAM as well and the i3 is still a dual core so you can get the i5-750/760 or go AMD Phenom II X4/X6.
no, if you already have a core 2 duo dont bother switching to a new motherboard, cpu etc. Core 2 quads are plenty fast, faster than i3 for video encoding. Too much money to swap over motherboard, cpu and RAM, when you could just upgrade the CPU (depending on the motherboard you have) and have a very fast system. But really, just try encoding video with what you have, it may be fast enough for you. List your motherboard and full system specs if you want us to help you decide.
If your just looking to dabble in this then a C2Q will be fine. Its not like this is for work or anything like that right? If you need to shoot a wedding then edit the footage to show during the reception (work purpose) then a fast i7 would be better. Let us know the specs of what you have now and how fast you need to convert so we can help you.