Sippy cups come in all shapes and sizes. I think I've tried them all. You've got some that have two pieces: the cup and the lid. Then you've got some with three pieces: the cup, the lid, and some kind of plastic that makes the cup spill proof. You got some that have four or five pieces: the cup, the lid, the plastic spill proof thing, the straw, the other straw, etc.
I've bought a couple at Wal-Mart before that have a cup and a lid and the straw is built into the cup. Don't buy these. They're only like $1 a piece, but they're not worth it. For some odd reason, whatever liquid is in the cup will "spit" out the straw. You could fill this halfway up with water and sit it on a table and leave it alone and you'll come back to the cup sitting in a huge puddle of water.
Then you've got The First Years insulated cups. These are the kind of cups that just come with the cup and the lid. I think Shorty has about 4 of these. These are nice because they're only two pieces. And no matter what you do with them, they don't leak at all. I have to say, I've tried these before (tried to drink out of them) and I promise you, I thought my eyeballs were going to pop out because it was sooooo hard to suck the juice out of it. Also, the cup doesn't hold a lot of liquid.
Then you've got the Playtex The Insulator Spill-Proof cup. These are three pieces: the cup, the lid and the plastic thingy that makes it spill proof. These cups I think hold more liquid that The First Years, but they're definitely easier to drink from.
I have to say that out of the three options I've listed above (I've got them all in my cabinets), in the morning when I go to pour Shorty's juice, I always grab the Playtex Insulator cups; that is, if they're clean.
Do you know of any other bigger toddler cups that I should try? Send me an email and let me know and I'll give it a shot.