Yes on the 512K upgrade, and Yes on the external 3.5" drive, both are
essential to full enjoyment of the A500. As to the monitor, the CBM monitor
is not a bad monitor, but it's not a super high quality monitor either.
Considering its price, it compares favorably with other monitors in the same
price range.
You might want a somewhat higher quality monitor (and a somewhat
higher price too) but check with your dealer for the price differences.
Don