well, i don't think that any of the apps you listed will take full advantage of the quadro card, so it would be a waste of money. its mainly a high end cad workstation card. the ati is the one that is best for playing games on, even better for games than the quadro. so that is the one i'd get. as for the dual-link thing, that is what is required to drive large highend lcd displayies, like apple's 30in. so to have 2x dual-links, you could connect 2 of apple's 30inchers!
Digital Audio G4/1.467ghz, 1.5gig ram, 16x Superdrive, 256mb DDR3 AGP 6800GS, zip, 2x500gig raid0 for 1tb on sonnet tempo trio, 10.5.4