For affectionate words and sounds, you could try... The delicious Natalia in her duo with Monica. Also, good things have been said about Kathy Moore and Lauryn May's duo.
If you want an out-and-out ***** bunny, try Jana Cova's solo card. Jana sets out to involve you in a sexual fantasy with her. She seems to enjoy entertaining voyeurs.
Like Starryk says, it's a matter of taste. If you like lots of oohing and aahing, moaning and the like, try Daria Glover with Carla Cox - too much for my liking.
Some cards are unconvincing because the slightest touch seems to have some girls on the verge and they moan at everything. It's almost funny. Read the comments.