I know you said nvidia and cheap, but have you considered getting a Matrox G400 or G450. I think Newegg has refurbished G450 now. I love these cards, but they can't really do modern 3d graphics.
I only make this recommendation since you said you won't be gaming. The G400 I once used had great looking 2d and dual head support that might be a lot better than a lot of cheap nvidia dual head solutions.
The G400 isn't that bad of a gaming card for older games like descent 3 and the like. I played quite a few games on it back in the day.