I noticed you didnt have any responses, and I dont have a very good answer, but here's what I'm doing
My DS is just 6mos today. We started solids 4 days ago, and I introduced his sippy the same day. With water in it. The kind I am using are like this :
http://www.amazon.com/First-Years-Spill-Proof-Colors/dp/B000096M59/ref=sr_1_5?ie=UTF8&s=baby-products&qid=1271714212&sr=8-5They arent valved, and he does an ok job holding them himself. They dont leak if you hold the upside down (as long as the top is on all the way - DH found that out the hard way
) and since the spouts are hard, it doesnt cause any confusion. DH has been using them now for 4 days, and not just for meals. When we come in from outside stuff - like trips to the store or walks in the stroller - I give him water then too. He doesnt drink a ton. I fill the cup about halfway at the beginning of the day, and he will drink about 3/4 of that.
As far as types go - I think it's up to your LO to tell you which one she prefers. I just went with these, as I think it will be fairly easy to wean from sippy to regular (but that's just me) and he took to them straight away.
Hope this helps