That's the really hard bit. A logical garage would include a 4x4 for winter and carrying stuff, a comfortable saloon for long journeys and evenings out and a sports car for weekends.
Choosing just one car is difficult - it would need to be a complete all-rounder. I would be tempted towards a 4x4 for the load carrying capacity and high driving position, yet would prefer a saloon for speed, comfort and roadholding on winding roads.
Hence the RS6......