My detox lasted a day and a half. It was in a moderately cushy suburban hospital, not a special detox unit, so my experience might be different than others'. I brought a couple books, watched a lot of TV, slept. It was boring, not gonna lie. BUT. I had a fantastic nurse (who later became my sponsee sister) who talked to me for as long as I needed, risked her anonymity to keep me company and tell me what to expect in rehab... I don't know that I'd have kept going to meetings for as long as I did if it hadn't been for her.
My two cents: do it. Bring books, bring movies, bring whatever you need to keep you from going crazy, but do it.