Hey, Marko. I found one I think you might like. The download requires users to sign up with the site, but the program was created at Tufts University, and I think their main interest is that users are able to update the program. Submitted e-mail addresses do not require validation, and there is a choice on sign up to receive e-mail alerts of updates. It was a simple process without the validation.
I have a mind mapper already called FreeMind, which is very basic. This one is over the top in with features and doesn't compare with FreeMind. First, the interface is much better. Also, Images and URLs can be added to nodes, and there is even a feature for creating a presentation style file which moves through the map process. For anyone with FreeMind this would be a big step up...
Not sure about the download process, but the program was clearly created by some of the staff at Tufts University, so at least it should be a safe download. Seems safe to me so far, anyway.
Here is the link if you think it is worth a look:
http://vue.tufts.edu/download/index.cfm