Some additional considerations:
If you use a PicassoIV in an A2000, you have to physically 'cut' the card to make it compatible with the A2000's video slot, which is different than that of the A3K and A4K - not a big deal for most people but I never wanted to do that to my PIV's, so I put in a C64/3D instead and have been more than satisfied with the result. I also have a DKB Wildfire 060 in mine, though so that helps, of course.
If you are deciding between CGX4 and Picasso96, I tried both but could never get CGX4 to work, whereas Picasso96 worked first time I installed it and has been trouble free the entire time.
You don't need a flicker fixer with the C64/3D, so long as you use a mode promoter like NewMode to make sure any screens end up being Picasso96/CGX screens - note that even so, some apps will not allow 'promotion' (such as the version of ViewTek I have, I need to upgrade it) and thus since no NTSC/PAL screen is avail, they simply won't work.
Note also that in an A2000, you have only 1MB of ChipRAM, so getting a DKB MegaChip (or similar boards from other mfrs) is a good idea to double to the usual 2MB of Chip RAM (seen on A3K, A1200's and A4K computers)
Good luck!
kevin orme
amiga university
www.amigau.com