HELP!!! So many choices

Well since my band has three guitarist and no bassist I am switching to bass. I have been doing a lot of reviews. I have made up my mind on an ampeg classic svt head, running a 4 x 10 cab. I think this will keep up with the twin mesa boogie dual rectifiers. My problem is: I need to know a good 5 string bass. We play heavy metal like godsmack tool stuff like that, but we are also talking about melodic stuff like staind. I need a good versatile guitar to handle both heavy and a nice warm sustain. I am selling off all my guitar stuff to buy my bass rig. I am trying to keep it around the 5 or 6 hundred dollar mark.