Stainless
I stick with Stainless Steel and have a Kleen Kanteen in the 27 oz. It fits in my water bottle cage (a bit loose but all right) but it is sort of difficult to drink out of, even with the sports top. I ordered a new sports top (2.0) from REI and hopefully that will remedy the problem 
Many other manufacturers make stainless bottles too. I've been eying the Camelbak Stainless bottle. I've also seen the Nathan Stainless bottles but do not know how well they work.
Ana
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2009 Lynskey R230
Trek Mountain Track 850