Hi William!
Thanks for stopping by and asking a question! Hopefully I can give you some good advice!
Of the times you've listed, I personally prefer the February and April dates. While mid-Summer trips can be a lot of fun, our family prefers the cooler weather of the Spring PLUS, its a great diversion in the middle of winter!
April vacations are often a great time to visit since the
Flower and Garden Festival is in full swing at Epcot. The landscaping and special events at the park add a nice touch of Spring to the air! Although, with the week you've chosen, I will note it is Spring Break week for many schools, as well as Easter week. This does translate, usually, into higher park attendance BUT that also means longer days in the parks! If you're a night owl, this works well! You can stay and enjoy a nice dinner at the parks and hit the rides in the late evening!
February is a popular time with our family as well. Its just far enough after the holidays that we look forward to time off. If you're a sports fan,
ESPN the Weekend is often held at Hollywood Studios during late February. Dates for 2011 have not yet been announced, but I know first-hand that quite a few of the Moms Panelist enjoyed the events last year!
And, last but not least, you may want to check out the
Special Offers page of Disneyworld.com. You may find that one of your weeks is more budget-friendly than the others and that can be a factor to consider!
Have a great time at Disney World!