I too have heard good things from the ozone generators. I have a small one that sits in the fridge and it seems to do a good job. Either that or we just eat the food quick enough.
Febreeze makes a shampoo for carpet cleaners now and it works pretty well. Ours had a bit of a lived in odor as it is old and when the PO re-carpeted, they just put new carpet over the old. After cleaning every square inch I could get to with the carpet cleaner, the smell is about 93% gone. I may try again with a small amount of vinegar added to the cleaner or maybe just see about getting one of those Ozone machines.