If money isn't a worry, then the A4000 is your friend.
You'll have a lot less compatibility and reliability errors with an A4000, as well as a lot more to expand phsyically (though if you get a tower that doesn't matter anyway).
With an A4000 you know your Zorro III slots will work perfectly, your CPU will be more reliable with the extra cooling, specially if you're going the PPC route (which I strongly recommend - get the 604e@200, 68060@50 CSPPC if you can as the 233 is a little less reliable I think), and from what I've seen they just hold together better.
Of course I'm biased - but you're not having my A4000.
Nonetheless I still say A4000 every time.
