There's a lot of hype surrounding the "NoSQL" databases, and it really doesn't help that they've been placed in an adversarial position. Are they good at something, or just not SQL (* sigh of relief * )? It's too bad that branding has taken hold - it obscures the things that make them individually interesting. CouchDB and Tokyo Cabinet (for example) really don't have that much in common.
I really like Redis, personally, but I also like Postgres and SQLite. They're complementary!