I'm not really a pack rat, more of a bottom feeder. I've got a bulk roll of Tri-X in the freezer that expired in 2001. Its twin, rolled into cassettes last summer, has been going along very well without excessive fog or any notable loss of speed, so I'm happy with getting the two rolls for less than a single new bulk roll would have cost. Likewise, I have two boxes (50 sheets each) of TXT 9x12 cm that I got from J&C Photo, expired in mid-2004 (clearly labeled expired, discounted -- J&C are honest folks). I paid a bit less than half retail for them, and I'm very, very happy. One box is in the freezer, the other with my plate cameras.
And I've got some Kirkland Signature ISO 400 C-41 that I bought more than ten years ago, and was stored at room temp most of the time -- still works just fine (processed a couple rolls last week, satisfying myself that the Vivitar P&S I just appropriated was worth feeding).
No big quantities of anything, though -- I can't spend $200 to $500 or even more on a single film order like some folks do, I pretty much buy it as I use it.