Assistive Tech is based so much on individual needs that I would have a hard time ranking it that way. Have you been to www.closingthegap.com/ ? It is a fantastic AT resource, and my favorite place to research AT. The magazine is subscription based, but the forum is free. Personally, I think the forum is the best part of the site - it is a great place to read up on anything AT; everything from low to high tech interventions.
Wow--I could go on for hours about my favorite tools--it really depends on the population you are working with. Overall, one of my favorite software/hardware combos would be Intellitools Classroom Suite, Overlay Maker 3 and the Intellikeys keyboard, all available from Intellitools. This suite allows educator to create customized curriculum and learning activities, provide access to a variety of learners, including those with significant physical disabilities, and collect data. The company also has an Activity Exchange filled with hundreds of Intellitools activities created and shared by educators all over the country (and probably internationally, as well). I can't tell you how much time downloading these resources has saved me over the years!
I have a number of other favorites listed on my blog, Accessible Educational Technology.