Clara's best song is probably the chillingly gothic "Scandal" by Candy Taylor, but in recent times I've also been really in love with "Telephone! Telephone!" by Denise. It has a sort of unique flair to its production, but a supremely catchy composition and a razor-sharp attention to sonic details cause it to be not only as punchy as any great eurobeat song, but superlative within the genre. The sabi is a particular highlight, but Clara's vocals work extremely well with the song and make it really bounce.
For me; it would have to be the first one I found out it was here singing. The classic "Just A Game" by Vanessa. In fact I can actually say my favorites would be the Vanessa hits like "Eternity", "Special Desire", "Hey Hey", "High High""You Don't Give Me Love" or the gorgeous "Diamond Eyes". On Delta; I'd have to say "Guilty" by Denise or "Burning LIke A Flame". So many to choose from.