I'd like to second Stacey Kent. Her "Breakfast on the Morning Tram" is a great new album. "Collection" and "Collection II" would also be a great place to start. Evidently she's really big in the UK. I only just heard of her last week, but she's now on the heavy play list. Her voice is really pure and light. She really makes good use of dynamics and always has a great band behind her.
Dave
Dave