I guess it depends on whether your wedding/portrait stuff is paid or not. If it is, then I'd get the 35L, because right now, if you get a church ceremony with no flash, you're basically stuck with only one low-light prime. You'd have to go pretty high ISO with the other lenses.
The 16-35 will be better for landscapes and travel, but, it leaves you basically all at f/2.8. And, depending how how much you travel with just the 24-105, I might even consider swapping that for another prime (85mm, 135, etc).