The 3000 has a scsi II controller Native. All Amigas are scsi II, generally the 50 pin internal ribbons, or they use the db25 25 pin external cable which is exactly the same on the mac. You should be able to use any external scsi device with it as long as you have the right cables and a terminator on the end. It is pretty simple. If it doesn't have a hard drive, start out with a < 4 gig scsi II drive. It will be the easiest for you. I'd say 99/100 times the 3000 will unless specifically stated otherwise. The 3000 came with a hd by default, it was a 3d animation type system. Great system, and I believe the only true 32bit amiga. That's why the 3000 towers are so highly coveted. It doesn't have the aga chipset like the 1200 / 4000, but it's supposed to be much faster that its aga counterparts due to its 32 bit nature.
The only issue I can think of is you can not write Amiga Floppies from a pc without a special controller card and Amiga compatible floppy drive. The controller you need is a catweasle for the pc. Otherwise you will hae to transfer the disks over to the Amiga to write to floppy on Amiga hardware.
Congrads on the 3000!