Seems like Hawk was the only one to really address the OP's question. Issues I have dealt with first-hand.
Coils are a big issue, due to oil leaking in. Ask seller if they have ever noticed this, or maybe you can even take a look at the coils before you purchase. Causes car to misfire and run uneven. Many here have purchased a full set of 8 from ebay for well under $200. Ask seller if they have ever noticed this, or maybe you can even take a look at the coils before you purchase.
The valve cover gaskets are not too hard of a DIY job with the right tools and patience. I believe the passenger side gasket cost me under a hundred dollars.
Window regulators are notoriously bad. Once you replace one, its not a bad DIY job. There is a very good write-up on here and you can find the regulators on ebay for less than at the dealership.
Sway bar bushings eventually harden and lead to a loud clunk from the front of the car. Easily replaced with Energy Suspension bushings (about $25) and installed by yourself or a repair shop.
Leaky headlights can be resealed with RTV sealant or you can easily buy a replacement set; same goes for the tail lights.
Like any used car purchase, just look over the car very carefully and maybe even have a trusted, 3rd-party mechanic take a look at it. Its insane the kind of deal you can get nowadays on an LS compared to when I purchased mine 3 1/2 years ago. For the looks, ride, luxury features and price right now, I dont think she can go wrong.
Any car will have its fair share of problems, you just have to have a good source of information (like LVC) and some common sense not to always rely on someone else to repair your car.