I'll just put in another gratuitous advertisement for my Soma polycarb/polypro/polysomething bottle.

I abuse my bottles horribly, don't wash 'em for days, leave 'em in the sun, let 'em grow unusual colonies of biological oddities unchecked.

None of those cooties have been able to take hold in my Soma bottle. And it has never tasted like plastic.

A quick scrub with dishsoap and a bottle brush, and all my bike-bottle sins are forgiven!

http://www.somafab.com/bottle.html