What are your favorite free, online language dictionaries?

I've got some opinions on this one (ALC, holla!), so I'm putting together a series of posts for the best free online dictionaries between English and each of Japanese, Chinese, Spanish, Portuguese, Italian, French, and German (which is probably the rough order I'll do them in). I'm also considering adding Korean and Russian to that list (two languages I've been known to dabble in), but since I don't use those as heavily my opinions are less-well formed.

Before I do, however, I'd like to put a call out for any of the free, online dictionaries that you might like. I've found before that sometimes the best dictionaries don't turn up easily in searches, so I thought I'd see if a little crowdsourcing might be able to find me some new and interesting hits.