Steel/Carbon - intersting combination. Not seen much over here. Steel is generally thought of as a bit 'old skool' - although there's LOADs of people who swear by it. My winter bike is steel and I love it.

Alu/Carbon is the most common combination here. Leading Italian frame builders like De Rosa and Pinarello have started doing very groovey things with the stuff .

Check this out.
http://www.derosanews.com/ Click on Products/Bike de Rosa then have a squint at the Merak. ( Sorry - it wouldn't let me do a direct link)

They use a special process on the alloy and the top tube has this cool sculpted effect.