— - I'm in the process of making a word game as well, and I'm using an XML word list to store everything. There are currently 110,000~ words, and searching through them is very fast, though I've done a couple of things to help limit the number of nodes that need to be searched at any given time.
There's extra overhead in the file, of course, due to the need for tags, but the ease of searching, for me, far outweighs the cost. The entire file is 2.5mb, but this also includes a separate list of about 12,000 9-letter words (something I needed specifically for my game).