the best A2000 accel out there, in my opinion, if you can find one, is the DKB Wildfire 060, because not only does it have lots of RAM capacity, but it also has an '060, SCSI *and* Ethernet built into it - and the ethernet is RJ45, not older coax. Miami supports it, probably OS 3.9 does too (although I only have OS 3.1 on mine). It goes in the CPU slot so you don't have to waste a zorro slot and it doesn't get in the way of other stuff at all.
Other good cards include the Blizzard 2060 (probably almost as rare and hard to find) or there's a couple 040 cards (Warp Engine, I think is one) that are also good at 40mhz.
The main thing with 2000s is that even with a graphics card (these days unless you can find a used PIV and you want to cut it to fit (because on an A2000 unlike A4K's and A3K's, you have to) you are likely going to use a CGX64/3D like me, because that's one of the only ones left out there to find (the GVP spectrum is another choice but not near as good or fast). The CGX64/3D is a good card, but also unlike A3k, A4k or A1200, you have to usually put up with 1mb Chip RAM, unless you can find yet another DKB product, the MegaChip, which adds another 1MB Chip Ram -
if using OS 3.9 this isn't nearly the hassle as with 3.1 or earlier, because you can map much of workbench, etc. into Fast RAM via config settings at bootup. In the case of the older OSes, no go - I run into this when even using TVPaint and I want to open a large digi-photo or something, I run out of chip ram and it tells me to free up memory (unlike Winblows, running out of ram on an Amiga in many cases merely gives you a message, not a fatal error or brutal hard-drive swapping, in part because the Amiga generally can't use virtual memory anyway).
But otherwise, I agree with the previous poster, the A2k is one of the best to deal with, FAR better than the A3k desktop (oh the humanity!) even though the A3k has that cool flicker fixer and likely faster SCSI on board (a2k doesn't have SCSI on board).
Happy computer building!

kevin orme
amiga university
www.amigau.com