Well: a) you really, really want something better than a Rage 128 card in the Cube anyway, certainly if you plan to run OSX; B) something like a Radeon 7500 works well and would certainly match well with the 20" screen; or c) I could trade you a 17" studio display and a widget of your choosing for a 20" screen, one of which I have been looking for ....

I am 175kms down the 401, but if you are interested in old Mac gear, my place is a little Shanghai-La.