Help with Lens choice for completing my kit

I've got a 5DMKII and I've acquired a few prime lenses over time and don't own any zooms....just a personal preference.  My kit is "fairly" complete on the long end for the type of photography I do, but I'm obviously lacking a bit on the wide end.  I'm also lacking a bit with regards to having a  "fast" lens in the normal range.  I'm hoping to get some advice for a lens to complete the kit  Here are the lenses I own (all Canon):

40MM f2.8 Pancake

85mm f1.8

135mm f2.0L

200mm f2.8L

I've owned a 15-85 in the past, and looking back I primarily only used the wide end (15) for travel (ie tight European streets, Architecture, Landscapes, etc...).  I didn't use it often, but when I needed the wide end, I was glad to have it.

One option I'm considering is to "rent" a wide angle lens only when I travel (ie from Lens Rental).  I could rent a 16-35 2.8L or 24mm 1.4L for the few occasions when I really need a wide lens and use the money saved to purchase fast lens in a focal length that I'd use more often.  If I went this route, I'm considering picking up either of the two lenses below to help fill out the mid-normal range with a faster lens (and possibly selling the 40mm Pancake....or just keeping it, since it's so cheap and relatively good lens).

Sigma 34mm f1.4

Canon 35mm F2.0 IS

Just curious to get some advice for the best lens to fill out my kit.