Echoing the above replies, I completely agree - go midweek!
Weekends the parks are open later, but you spend the majority of the time in crowds and queues and it can be a rather unpleasant experience. I have found that on one day, during the week, I was able to ride pretty much all of the rides (BTM, SM, Crush, RnRC, Indiana Jones, etc) on that same day - whereas when the weekend rolled along - I only managed to ride FOUR rides that entire day!! It was awful and that evening I couldn't help but think I had wasted a day queuing when I could have seen much much more...
Definately go for a weekday! And as the others were saying, although the park closes early - you can still be very Disneyfied as you can spend time in Disney Village in the shops or having a meal with the characters at Café Mickey. My personal favourite thing to do in the evening at DLP is to have a walk around Lake Disney and explore all of the hotels. You can walk in and out of all of them and there is so much to see and do in them all - characters are still around in the evenings for Meet and Greet at the Hotels also...
Whenever you do decide to go, you're going to have a fantas'mic' time!!