Oceanborn is my favourite release of them, but I don't really like Tarja that much. Annete is a great singer, but this sopran-voice fits better to Nightwish, I think. :/
I listen to Tarja's solo, too, but after that I read this letter from Tuomas, Marco, Emppu and Jukka to her, she seemed way more dislikeable to me.
Anyway, it's mostly about the music, and I love their music.