General Language Practice

BBC English Language Learning
Excellent all round language development. Topical. Changes regularly. Choose either 'Courses' or 'Features'.

English File
Accompanies the English File course book series, and has lots of useful exercises for grammar, pronunciation, writing and vocabulary which can be used independently. Just choose your level.

Learn English
Grammar and vocabulary, listening, writing, games, tips for IELTS.

English as a Second Language
Site with a lot going on, but some useful exercises – e.g. self-check dictations and sentence structure exercises under “writing”.

Videos (with subtitles and vocabulary exercises)
Lots of short videos, filtered by “academic”, “business”, “social” etc. with follow-up exercises.