I dont use one either -- I got a really cute Happy Tushies one from the TP and tried it for a while but felt like I was just adding more to the wash than was necessary so I stopped using it. I dont put poopy dipes in there though, just wet.
I use one of those chrome pails with the foot pedal. So it has a plastic pail as a liner anyway. And I find it just as easy not to use a liner. A quick spray of bathroom cleaner and it is good to go. I have found that keeping my lid propped up is smell free, but a closed lid, watch out. Same principle as my Bummis bag that I used while on vacation. Yucky!
I've never used one. We have two diaper pails, and so I use one, and then when I unload it into the laundry, I let it air out, and start using the other pail (which is sitting by the washer airing out from its last turn). So we alternate back and forth, so that one pail is always sitting open to air out while the other is used. No stinkies yet.