I'm not as interested in the 990, but the DT880 has been pretty much my top pick for a while now. However, I am slightly concerned with regard to the impedance-- at 600 Ohms, the DT880s are going to max out my card. They should be driven fine according to what others have said in the past, but that's pretty much the only reason I haven't already picked up a pair.
Well, that and the release of the HE-300. Since they're in the price bracket I wish there were more reviews (I've already read Headfonia's and the one or two threads here about them).
Thanks for the input though, it's just one more thing to vouch for the 880s.