I moved into an apartment once that had a smoker smell to it and I found a thing that you hang in the closet that pulled the odor out. It was a solid gel thing that came with a hanger. Unfortunately, I don't remember where I found it, but you may want to look at places like Bed, Bath, and Beyond (or online).
Like someone else said though...put costs for updates into the contract. You are probably going to have to do a lot of work to get rid of the smell. And, plan on getting rid of the curtains. I dated a smoker once and all of the curtains in his house were yellowed because of the nicotine.
All in all, I personally don't think I could buy a smoker's house. I dated that smoker in my early 20's, but I don't even want to be friends with smoker's anymore. It's just too much.
-L.