RE: What is your favorite sippy cup?
I really like the Babies R Us brand sippy cup. It has an attached valve (can't lose it), cloudy plastic, and bumpy rubber grips for your child's hands. They have *never* leaked, even when DD sleeps with a cup of water fallen on its side all night. I also use regular Playtex with the valve, which is pretty good, but they sometimes leak and sometimes my daughter can shake or throw the valve loose. Not so with the BRU cups.
Advice and commentary on living overseas
DD1 15, DD2 12, and DS 9