I had my first A4 for 8 years and second A4 for 9 years. The 2 week old S4 could easily be a long termer too. My second A4 was pretty bullet proof and very reliable....pretty much no surprises.
My fully optioned S4 at list price in Australia was about $144k. That is with an exchange rate where an Australian dollar buys 93c US. That is just shy of 2.5 times median wages for a full time employee in Australia, before tax (and upper tax rate is about 50%). So that kind of changes the perspective on affordability and depreciation (a very big chunk of change is left lying on that road just outside the dealership).
So, option it big, love it to death, and if i just fall in love with an RS6 I will have to get two jobs.
2014 (B8.5) S4 Avant, Sepang Blue, Sports Diff, 7 S-tronic, 19" Rotor Titanium look, Adaptive Dampers, Dynamic Steering, B&O, Carbon Atlas inlays, Black Nappa, Black Headlining
2005 (B7) A4 2.0TFSI Quattro S-Line Sedan Graphite 6MT
1997 (B5) A4 1.8 Sedan 5MT - some silver colour