Have to go with primes m'self.
The 50L, the 85L and the 135L. The 50 & 85 are somewhat 'soft' wide open, but in a pleasing way and unless you are doing twighlight work, no one shoots at 1.2 anyway.
If these are out of your reach (and they ARE expensive), the 'standard' 50 1.4 and 85 1.8 are nothing to be sneezed at. The 50 & 100mm Macros are favoured by some for portrait work, but are very, very, sharp. Not something you always want!
To get a bit silly, both the 200 & 300mm 2.8L make great if slightly unwieldy portrait lenses!
If 'twer me, I'd go for the 135 f2L (though NOT the soft focus 135. Its a dog). Its a long favoured all-rounder and my FD version is the sharpest non-macro lens I own.
H might have a differing opinion, but he's obviously skiving-off somewhere!
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