http://www.dremel.com/en-US All the images are from their website. If you go there, they have a lot of information and have stuff you can download.
This post will be about their tools. These are the ones I own or want to own.
The top one is the 10.8v cordless. This is a little heavy on the backside but works great. It really holds a charge. I used it a lot while at CHA to cut apart keys and yard stick pieces. It is a great tool. I used it with the multi-vise.
The 2nd one from the top is the 300 series. This is a great beginner rotary tool. It has everything you need. You should always look for variable speed when you get a Dremel.
The 3rd one from the top is the 400 XPR. That is one to get if you are serious about your tools. I have one. I don't use a lot of the attachments though. It has a sleek body which makes it easy for my small hands to hold.
The 4th one from the top is the Stylus. I got it as a gift. Actually, I got it twice. It is cordless. I don't use it a lot except for engraving, polishing, sanding, etc... I am not crazy about this one. It is nice to have though if I am doing multi-step things. I can have a tool for each thing and not have to change out accessories.
The bottom one is the first Dremel I ever bought. It is the 395. It is a workhorse. If you find it somewhere, it is a great first Dremel to get. It was basically replaced by the 300 series.