I've known a couple of mini schnauzers. Major personality...though the two were very different.
Dachshunds are entertaining but insane. At least, that's how the five or so I've known now have been. I dunno that I'd want to have 'em again.
Personally, though, I'd say Lab/Border Collie mixes are just about perfect. Not that I'm biased or anything.
Dalbradors are awfully nifty too. ;-)
I just love retrievers. I think I want something that's at least mostly retriever.
Just not a retriever/chihuahua mix.