On a 6003 - I have used mostly the 60 mm Schneider, which, for some reason, seems to impress as the best lens ever. Its wide, detailed, sharp and has great bokeh. Just special. As a single lens camera, this is the one to have.
Its companions are the Schneider 40 mm, for the wide shots, architecture, and if the digital back ever joins the family. Its the same size as the 60 - quite compact. It might have a bit of give in the corners, but its pretty amazing too
The Schneider 90 hasn't seen much use, but its fine, with its macro setup quite versatile.
And a 55 PCS, for shift. Its a bit too big and heavy, but does give fully automatic metering with shift. Its almost easier to shoot with the 40 and crop, but I like to shoot full frame. There was a 150 Schneider in the family, a really good lens, but it was never used that much. But I think (if the back ever comes) I'd try to get one again. Of course, the 120 is faster, so that's appealing too.
The attachments are in existing light - one with the 150, handheld, the other the 55 PCS.
Geoff