Fernando,
If you want to spend $400-600, you should look at the Sony Laser Library,
the SunMoonStar bundle, and DAK. Those seem like the best deals based on
the reading I did. I bought the Laser Lib because of the particular mix of
disks it had, but a lot of people would prefer one of the others.
I think the SB PRO has a port on it to run a drive, and you should check
into getting a drive that'll work with it. Especially if you're interested
in the new MPC multimedia disks which the drives I mentioned above aren't
spec'ed to handle. Since you already have the SB, you might be able to
hit your target price range, which is a little low for a complete MPC kit.
Ran