thats actually a tougher question than you'd think.... however i'd say an audi is right for you, not sure about an A6 tho. The new A6 looks awesome, however, it
isa first year all new car. Personally, i'd rather wait on it a few years so tehy can get all the quirks out (yes.. even audi has quirks... )
On another note, a girl friend of mine just sold her 530 - she hated it! iDrive was bad, trips to the dealer every month for another problem (all covered under warrantee, but still a pain)
If you decide to go the route of the new A6, wait around for the 4.2 V8 to be more available. The 3.0 is underpowered for the A6.
Look into an S4 if you have the means to get one...
good luck, keep us posted