K.R.
I've always liked the bottles that look "bent" so the air is pushed up out of the way. Playtex Ventaire and Evenflo are my favorites. I used them for my first child 3 years ago, but tossed those because of BPA last spring with my second child, I tried a few other bottles, but ended up back with Playtex and Evenflo (both are now BPA free).
Best of luck to you!
K.