You need a practical response. You need a practical lens. Hopefully your 24-70 f2.8 is the MkII version, in which case you have a brilliant quality 24mm lens. Getting a 24 f/1.4II or 24 TS-E would be very nice, but until special needs reveal themselves, stick with the 24mm end of your zoom.
Wider? The 14L is a brilliant piece of glass, but like the astounding 17TS-E it's somewhat limited for general use. Really, the 16-35 f/2.8LII is going to be a far more useful, robust lens than any of the lenses mentioned so far. The other lens to flesh out your collection is the lens that a great number of photographers consider their most used, best loved and almost standard lens...the 70-200 f/2.8isII.
Sorry but here's the Dad in me....While you say you don't mind giving the credit card a good beating and say "what the heck I'll worry about it later", keep your feet on the ground and spend responsibly. Most photographers add lenses as the need arises, not for what they think they may need at some future date.