I would reccomend only buying one bottle of a specific brand until you see what your LO likes. They may hate the bottle you like and then you are stuck with extra bottles you can not use not to mention the $$ you spent on them.
Early on we tried Avent, then the Breastflow bottle by First Years, then Dr. Brown's. My LO refuses the Avent from both my husband and I. She will only take the Dr. Brown's from my husband and will only take the Breastflow bottles from me. We are guessing the difference is b/c the Breastflow is more like a breast and I nurse her so it is all she will take from me but I do not use a bottle that often these days now that she is finally nursing!!
More recently we started using glass bottles to avoid issues of chemicals in the plastic but daycare will not use the glass for safety reasons (which I agree with). The chemical issues are covered in this thread:
http://forums.llli.org/showthread.ph...hlight=bottles in the Around the Refreshment Table section. I'll bump it for you.
Keep trying different ones and you will find one that your LO likes.