Our favorite times of year to go are:
End of September through end of October - Specifically, anytime the week AFTER Food and Wine Festival in EPCOT begins. The first weekend is just over crowded. The beginning of September is usually a bit less crowded, but the weather might not be on your side. We know this because we spent three days sequestered in our hotel waiting for Hurricane Frances to pass in September 2004.
First half of December - The parks are all decorated for the holidays but the crowds are not as large as they definitely will be later in the month. The weather is chillier than October or May. We've never been to a hotel pool during this time and we tend to stay at a hotel with a 'warmer feel' - Animal Kingdom Lodge, Wilderness Lodge.
January - We usually go for a long weekend in January, just to get away and put our faces in the sun. The crowds are minimal! Although this trip is usually only a few days for us, it is well worth it! Temperature can be downright chilly or pleasantly warm.... it's a crapshoot.
One of my go-to sites for all things Disney is All Ears. They have a great section under Planning which also details the best times to visit.
Tutto Gusto Wine Cellar for a quick sandwich or snack. This place is only about a year old and they seem to still be working out their menus, but it's our go to place to get out of the heat and crowds. It's located in EPCOT in the Italy pavilion. It is mostly adults and the staff is very friendly. Only downfall....cell phone service is very spotty. I am quite fond of their sangria.
50's Prime Time Cafe (PT) is located in Hollywood Studios and serves comfort food that is over the top. I will admit that we usually only eat IN the restaurant when we bring people to Disney World for the first time. When it's just the two of us we always go to Tune-In Lounge (which is connected to PT) and sit at the bar and eat. The bartenders (especially Dave, Alana, Julie and Enzo - they have all been working there for YEARS) are just the best! Here's a little interesting thing I found a few years ago while strolling the internet looking for some tips and tricks for Disney World. I discovered this blog and was reading about the Tune-In Lounge, and when I saw the picture at the end of their post.....IT WAS MY HUSBAND, OUR FRIENDS AND I sitting at the bar having a great old time. Here's the LINK. Ha! How crazy is that?
If you're a foodie, here's a great blog: Disney Food Blog (they are on Twitter also)
I've mentioned before that my husband and I are Disney Vacation Club members. The club gives us the ability to go to Disney (and other places) often. We enjoy it. There are hotels in Disney World which are designated as Vacation Club Resorts. The rooms in the resorts a little different from regular rooms at Disney, as they are larger, have kitchens, and multiple bedrooms. Here's the thing, you don't have to be a DVC member to book those rooms. If you go to the Disney site, they are referred to as Deluxe Villas, check 'em out.
Just a few tips to start. There are a many others to share! If you have specific topics you'd like me to touch on, comment below.