Don't get an A3000 unless it's completely updated with the latest Ramsey/dmac/buster/kickstart. You'll have to invest a lot of money and you'll still have a system worse than an A4000.
The A3000's scsi is slow compared to any scsi included with an accelerator, and if you want to use the scsi of an accelerator you have to perform the int2 modification.
The flicker fixer isn't IMHO a good reason to buy a 3000. I had one and I sold it fast to buy an A4000 and it was a very good move.
You have to put cd-roms and other devices in external cases because you can't fit one in the standard desktop case. On the A4000 you can put 3 hds, a disk drive and a cd-writer... two next to the PSU and one under the disk drive... It's one of the best designed amiga cases.
My A4000T case isn't so nice, I can only put 5 drives including 3'5 and 5'1/4... it takes a lot of space for nothing...
If you want PCIs you can´t put the pci bridge inside the A3000 case and you have to towerize it... if you want PCIs with the original A4000 case you can fit a mediator4000D or a G-Rex 4000...
If you buy an A3000 you'll find that you can't fill all the simm sockets of your accelerator because it doesn't fit well... on Amigas 4000 you can fill all the banks without problems...
Go for the A4000...
