My daughter is 11 months old and we've been doing a relaxed version of Elimination Communication since she was about 5 months old. (Basically, assisting her in using the toilet when I know she has to pee after she wakes up from a nap or when I predict a bowel movement is coming on). She has always seemed to enjoy eliminating in this way and I highly recommend looking into the method even though it may not be as effective starting later with an older baby, it will help you as a parent get in tune with your child's needs which is beneficially for potty training at any age.
I chose this method with my daughter because I feel that it is important for young children to stay connected with their elimination patterns. There are several books available on the subject, I borrowed one from our local library and got a lot of great information on it. Our family doesn't make a lot of money, so it just wasn't practical for us to use disposables for 3+ years. I bought a good number of cloth diapers and covers at the start and we use those instead, which if you aren't already using you might want to consider once you start potty training to help your daughter "feel" when she wets herself. (disposables are so good at wicking moisture off the skin that often kids don't know when they've gone!) Gerber also makes some "training pants" that are basically like padded undies that absorb some of the spills but the child can still feel when she wets. (unlike pull-ups, which in my experience with my older step-son only prolonged diaper use). These do get damp on the outside when the child goes so they are best for use around the house. There are also training pants available with PUL covers on the outside to make them more waterproof, but I like the Gerbers because they are so cheap I could afford to buy several packages of them.
My 5 year old step son was diapered exclusively in disposables and then started pull-ups at age 3 and still had no interest in going anywhere but in his diaper. I think that he was so effectively "trained" to go in his diaper it made it very difficult to change to using the toilet after doing it one way his whole life. He is 5 now and in preparation for kindergarten, we began a new method of training him at age 4.5. For a month we used a timer to remind him (and us) to take him to the potty every 45 minutes (with much protest from him) and about 4 months of "potty rewards charts" (star sticker charts that lead to a big toy like an action figure after he gets a certain number of stars) With lots of positive reinforcment, he is finally getting there. But it has been a big struggle and I wouldn't wish that kind of delayed potty training experience on any child. I think it affected his self esteem greatly, even though his parents were giving him a lot of positive feedback and trying not to make him feel ashamed when he had an accident. I firmly believe that the disposable diaper industry has way too much sway in influencing the ways that we teach our children how to take care of their bodies.
Another tool that can help a pre-verbal child learn to communicate their need to potty is American Sign Language! We do the ASL sign for "potty" when my baby uses the potty and that way even though her verbal skills are still developing she can sign to me when she needs to potty. She is just starting to sign back to me after a couple of months of showing her the sign, and she usually signs to me just as she's going in her diaper, but I feel good knowing that she is learning to communicate with me about her needs! Once she starts communicating more predictably we will probably try to start using the toilet regularly. I have really enjoyed elimination communication verses the disposables-until-kindergarten-route because the way I see it, EC is not so much focused on the end goal of being "potty trained" but on the small successes on the way.
So, all that aside, to answer your question, my favorite potty seats are the Baby Bjorn "little potty" and the Baby Bjorn potty insert that sits on top of a regular toilet. I think I ordered both online either through the Target or the Toys R Us website. It is nice to have the option to pick between the two. Often I will go potty first thing in the morning, put the baby on her potty on the floor and we will both go together! Be warned, though, the Baby Bjorn "little potty" is very small, it is the perfect size for a child that is 1 year old but probably too small for a 2+year old. Baby Bjorn also makes a toddler sized toilet that looks nice but we don't have that one. Be careful with the on-the-seat inserts because we had a cheap one that dripped pee all over the place and was disgusting. I guess many of them do that and after doing some online research I went with the more expensive ($30) Baby Bjorn insert because it was the only one I could find that was constructed well enough to not collect urine inside of it. The great thing about this insert is that the 5 year old loves it too. It is an attractive design with a cute bear on it that the kids seem to like.
For more information on cloth diapering, elimination communication, or American Sign Language, these are my favorite online resources:
http://www.simplecloth.com/ (local diaper store owned by a really nice lady)
http://www.diaperfreebaby.org/
http://www.theecstore.com/
http://www.aslpro.com/ (ASL online reference)