If you are on a budget I would get a iMac G5.
The 17 inch model can be had for $1299, even cheaper if you can get EDU discount. Even a eMac will do videoediting very well, and its only $799..
You will also need an additional 512MB RAM sick, shouldn't cost more than $80-$100.
Depending on how much video you'll edit (and how much music you have), might consider to get a larger HD. A new HD is easy to install in the iMac (it's often cheaper to replace it yourself than make apple upgrade it for you)
The 17 inch model can be had for $1299, even cheaper if you can get EDU discount. Even a eMac will do videoediting very well, and its only $799..
You will also need an additional 512MB RAM sick, shouldn't cost more than $80-$100.
Depending on how much video you'll edit (and how much music you have), might consider to get a larger HD. A new HD is easy to install in the iMac (it's often cheaper to replace it yourself than make apple upgrade it for you)