I went with XT because I wanted a 165mm crank arm length. Can't get that size in LX. I had to scour the net and ebay to find them! I got a used set (put it on my mtn bike), and a new set for the LHT.
My SO got a set of XT cranks in 172.5mm, very hard to find.
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Gunnar Sport
Specialized Ruby
Salsa Vaya Ti
Novara Randonee x2
Motobecane Fantom CXX
Jamis Dakar XCR