72mm SAXL.

Easily my most-used lens in this format.

Massive image circle, so perfect for Architecture.

If you mainly use wide angles on your current camera, it's pointless gettin either a 150mm or a 210mm. That's like getting a 50mm or 85mm for 35mm camera. Why would you get one of these if you shoot wide?

Also, if you're considering a 90mm (pretty wide), consider the f5.6/f4.5 versions over the f8 ones. Whilst they're more expensive (actually, compared to modern DSLR lenses, that probably should be written as "not quite as cheap"), they'll make focusing easier in lower light, especially in the outer areas of the shot. This will be important if/when you shoot interiors and/or with lots of rise/shift.