I LOVE several of these tools and have been using them for years! My all-time favorite is Big Huge Labs. There are countless uses for the Motivational Poster maker, Magazine Cover, Movie Poster, etc. My all-time favorite tool there would have to be the Trading Cards. You can create them yourself or even better let the students do it. This is such a great way to make important content visual and easily accessible. I have used them in regular content lessons and especially with second language learners. If you can find a picture and add a few words to get a concept across, how wonderful! If you didn't choose Big Huge Labs as one of the ones you wanted to investigate, I would strongly encourage you to spend some time there. Warning, it can be addictive!
This is a sample Trading Card I made at the site.
Of course most of us have seen or used Animoto by now. They do offer an educator's account, and it is easier to get it when you first open an account than to try to switch your account to an educator account later. Pick your photos; select some music, and let Animoto do the rest. Great for students, teachers, and even your family vacation.
Since I had already used most of the resources listed, I took a little while to explore Make Beliefs Comix. It is similar to a couple of other comic strip makers I have used. Students love to create a comic strip, and it makes a good project to prove they understand the basic concept being taught, no matter what the subject matter. It also allows students to write in other languages including Spanish, which could be beneficial to our more recent immigrant students who speak Spanish. A quick trip to Google Translate and students can create original comics in both languages. I can envision students using comic strips to explain some of the technical lessons in their own words such as How to Edit a Picture in Photoshop.
This was my sample comic: