With all the news about harmful BPA out there, I have stopped drinking from any plastic containers (although I solely breastfeed, studies show that some BPA can be transferred to infants via breastmilk), so the Hello Kitty SIGG bottles I have became very best friend lately.
I got two Hello Kitty SIGG bottles, both souvenirs from Switzerland - one from my mother and another from my sister. Incidentially, they both decided to get me SIGG bottle of this design:

I checked SIGG’s official website and saw two new designs, which looked like this:


But I think the ones I had look cuter! (hohoho) The only complaint I have is it is not compatible with straws and the openning is too narrow for Ethan to drink from it.
So for Ethan, I use BPA-free pigeon bottles with a straw or a Hello Kitty stainless steel bottle from Sanrio which comes with an extra wide openning. Sanrio gift shops (at least the ones in Hong Kong) have started carrying this type of bottles after pulling out most of their plastic bottles from the shelves.
Ours looked similar to this, but ours is bright red with a classic Hello Kitty design (too lazy to go take a picture of mine!) :

The best thing about these bottles is that the cap will never go missing when MaMa drinks from the small openning. And when the cap is off, the edges are smooth enough for baby to drink directly from through the large openning.

Another bonus - both bottles seem to do well in keeping liquids at reasonable cool temperature; i.e., the water or whatever inside won’t get boiling hot in the summer!
Impact from BPAs can include insulin resistance, brain and behavioral impacts, early puberty, altered hormone levels, and other reproductive problems (source: http://www.ewg.org/node/25574); not to mention the other harms we can cause by using too much plastic - It’s never too late to switch to a BPA free and environmentally friendly bottle - Act Now! : )