I've had my 2010 s4 for nearly a year now so here's a few things to consider:
*Oil consumption and leaks can be an issue on these. They do use oil and driving styles can effect it. Leaks tend to come from the rocker gaskets and timing chain covers. The oil consumption can normally be reduced with the updated pcv repair kit and changing to a thicker oil i.e 5w40.
*Mine has had the water pump recall done but I noticed it was still using a small amount of water so I changed the pump and it's been fine since. Whilst doing this I changed the charger belt and aux belt with the tensioners and idlers as well as the crank pulley. Search crank pulley failure and you'll see why it's best to do it as a precaution rather than wait for it to fail.
* Thermostat. I haven't changed this yet but I have heard its a case of when it goes rather than if it goes so I guess this should be on your list as well.
*Suspension. I just have the sports suspension with no ADS but both my rear shocks were leaking, they were the originals though.
Other than that's it's just the usual stuff. Mines a manual so I can't comment on the DSG but I have read some horror stories so definitely make sure it doesn't have any issues. Enjoy