What kind of help with questing are you refering to? There is a system built in by Blizzard that works fairly well. There's also lots of mods to tweak Blizzards system found here in wowinterface's
Character Advancement section.
Carbonite is alive still but may have way to much going on for your tastes.
Quest Helper is also still around.
I guess what I'm asking is what specific parts of the default interface did you want to change? The more you tell us the more we can try to help you out.