Of course, now the question is: what are they going to do with this $250M? The only new feature that has really come out of Dropbox recently is the API, and even that has been in development for some time.
I also use Evernote, which is a stark contrast. They roll out new features so quickly that it usually has many bugs and I have to learn a new interface ever year. I don't trust Evernote with anything critical (and I don't pay them) as a result. Just miscellaneous notes (To be fair, the Windows client finally seems to be stable and without any more glaring bugs).
One simple thing they could do with the $250m is to simply scale the business. They have had the same price structure in place from the start and are perceived as somewhat expensive at this point as competitors continue to lower prices. Lowering Dropbox prices will attract more paying customers which I'm guessing could be economical if they were 5-10x their current size.
I'm hoping for more work on the web API: OAuth2, sending/accepting shared folder requests, push notifications of file updates.
(I kid, I kid, huge dropbox fan here ;) )