I currently have a Sigma 50 f/1.4 and Canon 100mm f/2. I like them both a lot and will add a Canon 35mm f/2 (non-IS) as a lightweight walkaround lens as I often feel that the Sigma 50 is a bit too long and heavy for walkaround although I absolutely love the picture it takes.
I like this combination, 35-50-100 but occasionally I am tempted to get a Sigma 85mm f/1.4 to replace the 100mm f/2. I like the lightweight , fast AF and PQ of the 100mm but every once in a while I kinda want one more stop of light and a bit more blur. The Sigma 85 seems to fit the bill. The downside is that its bigger, heavier and the focal length isn't that much different to 50.
What do you guys think?