Ah got you, the sb400 isn't worth a lot so I'd skip that deal.
I mean you'll get similar quality on both, the d7000 will do better at high iso, but the 550d is still capable.
The main problem with shooting on the d7000 is you're limited to 30p, even at 1080p you can only get 24p, on the canon you can get 720p60 and 1080p30. Also with the d7000 in live view every zoom effectively becomes a prime, as if you zoom, you have to exit live view, zoom, then go back into live view, otherwise the exposure fucks itself up. Trust me it gets annoying, and you will just end up shooting at the one focal length.
550d takes some great photos, the buffer isn't the best, but it's usable. + with more money to spend on lenses it'll hold value better.
Are you gonna be shooting outdoors exclusively during the day? indoors too? night time? do you need fast autofocus for the photos?