I don't, except when I specifically want to check it on some matter. But for years it remained my mental reference because I knew it so well. When I wanted to locate a text the WT concordance was the best tool for me, since I had the NWT wording in mind. When I quoted something I had to "translate" it into "common wording". It's all over now, so I have to check it from time to time...
I always got "caught out" when I quoted by a Christian girl in my class since she could never figure out what translation that was. Though she was still in awe of just how many scriptures I had memorized. Even if you don't know what it means you know a lot of verses as a JW. I used the NIV bible for a few weeks and then just got fed up with Christianity in general. If I need something now I just use the CDRom or an niv website. But I rarely bother.