The 85/1.8 is a sweet lens, just a pity about the CA. If they fixed that and kept a similar IQ, price & size... mmm....Exactly my thought.
Improve it optically, less CA, little bit more colors and contrast.
New ring USM, aperture design and maybe improve the mechanics a bit.
... and having tried the Sigma 85/1.4 I was not really happy but I saw what could be possible.
85 1.8 II sounds great to me too, although I think 85 1.8 IS would be even better (as long as it doesn't push up the weight/size/price too much!) ... or perhaps an 85 1.4.
Other than that, 135 2L IS (I keep trying to come up with a way to justify adding a 135 2L to my kit ) and 50 1.4 IS (or even a 50 1.4 II if there are problems putting IS in a lens with a 1.4 aperture).
Maximilian - out of curiosity, what weren't you happy about with the Sigma 85 1.4? The reviews I've seen are generally very positive, with the only real complaint being some reports of AF issues. I've been thinking about trying to pick up one second hand to give it a go, so I'd be interested to hear what you didn't like about it.