help needed in upgrading to mini

Hi all! i just got my first mac about a week ago, its an 800 mgz g4, i'm quickly falling in love with it, but i am also realizing i am going to need to upgrade this thing fairly soon. The prospect of buying a brand new mac is daunting to me cause its allot of money to spend on computer but i know it will be worth it. My question is what should i get? Iam wanting to do some minor video editing (just taking out commercials)and burning to dvds. that is the only intensive thing i will be doing, (i might get a tv tuner for it as well) My biggest fear is that i will buy something and a year from now i will need to upgrade again, so i am wanting to make sure that the mac i get is good for me for a while, but doesn't hurt the checkbook too much.... also is the imac better then the mini? thanks guys for your help in advance!

Why do need to upgrade though if you're not doing anything intensive?

cause i was told the imac i am using now wont do it very well, plus its not running as well it should, (but its on 10.2.8, i have jaguar coming in the mail now) programs will randomly quit (safari, i.e. and netscape are the main ones that do that) other programs will run but not function very well. will these problems quit when i upgrade to jaguar?