I felt very little difference between the engineering culture at Yahoo vs other "popular" companies. And Yahoo's products are good- think YUI, Yahoo Mail (client side stuff), Hadoop, etc.
They asked me one thing that Yahoo! could improve upon and I suggested that they focus on making one service really really great, which can then, in turn, drive traffic to other services. And to drop poking their head into everything (My yahoo, groups, games, social networking etc can be dropped).
Its sad to see how Yahoo's value has fallen recently, since internally it seemed very vibrant and had the kind of atmosphere I would've liked to work in.