Unless you need Zorro3 for something, or if you don't have a decent video card and accelerator for your A2000, don't switch. Just re-read and saw your A2000 specs and what you want from an A3000. Don't switch!
Yep, my thoughts exactly.
My A3000 and A4000 are both 68040 machines, both ECS, both run Workbench 3.x. The only difference is the Zorro slots and the room inside the cases.
I have a Cybervision 643D in my A2000 which gives me a Workbench way better than AGA could provide, I have an "Amber" SDFF (It uses the same Amber chip found in the A3000 - an Indivision would be even better), I have a Buddha IDE card installed allowing 4 IDE devices (currently it boots from a CF card reader and runs the DVD ROM drive) and I have a SCSI hard drive attached to the CPU card.
The only thing worth adding would be a Deneb (it is in my A4000).