I agree. You shouldn't get an L just to get an L. That's frankly a waste of money, and it will not improve your photography. My mantra for upgrading gear is this:
It sounds to me like you just want the 'L' badge on your lens, rather than you have a pressing need for the capabilities. Getting a 'pro' lens will not get you 'pro' pictures.
So what are you currently using? All the specific lens advice here doesn't really mean anything otherwise.
It's like, women have jewels, and photographers have lenses.
My advice: Buy the most expensive L you can afford and/or the one that looks the most beautiful.