I'm attempting to write a program with a spell check/auto-complete feature. For this I need a decent sized list of the most common English words. The problem I've ran into is that there is a great disparity in the list sizes that I've found. They're either <1,000 words or >50,000. A list of <1,000 words is too short, and many useful words are omitted. However, a list of >50,000 words starts to become a little much for my algorithm (speed wise).
Anyone know of a list ~3,000-12,000 English words. Preferably in a .txt file. Also, it needs to have relatively non-restrictive license (ie, redistributable).