Well, I won't pretend that today's question was easy, because it wasn't. Certainly not as easy as the other two questions. But, after some consideration - I finally came up with my answer.
That's right, ladies and gentlemen…
Mokona from Magic Knight Rayearth
She's such a cute little critter and, even though I didn't think I'd like her (in fact, I thought Mokona would be unbearably annoying) I wound up thinking she was so adorable.
Although this is not one of the talking mascots (though there is a talking version of her on Tsubasa Reservoir Chronicle) she is such a happy, cheerful little furball. I love the way she interacts with the various characters on Magic Knight Rayearth and it is especially fun to see the different ways she behaves with each of the three main girls.
I would like to add, the most memorable Mokona moment for me was when she was hopping through the Forest of Silence with the trio of girls behind her. First she would go this way, then back that way - always going 'Puu!! Puu!!'. Probably the cutest thing ever.