The litter I use and swear by is Fresh Step. It is a clumping litter - and it clumps HARD. Like craftlady - I keep plastic bags and throw them out when full. I scoop about three times a day and only have redone the boxes - maybe twice in the last year or so. I just keep all waste and biscuits out and add more ltter as it gets low. Yes, it does make a mess outside the boxes but I keep a small broom/dustpan to sweep up when I scoop. There is no smell (unless a fresh desposit is made)
Just my favorite and they all use it and no complaints.
I also read here that the Wal-Mart brand is similar to Fresh Step.