This list is a pretty comprehensive list of, as the title suggests’ the top 100 tools for learning. Funnily enough Twitter is number 1 which does not surprise me. There is an interesting discussion of the pros and cons of social media here with some comments afterwards. Unfortunately the full text cannot be accessed from this site as far as I could see.
Evernote is something I have been introduced to on learning technology course which is free and cross platform. I would also advocate Google Drive and Dropbox if you haven’t got them.