I love the Davinci/Torani syrups. At last count, I had 16 different flavors you can use different combinations for variety (I like chocolate w/hazelnut and white chocolate w/raspberry) ... I am lucky, I can get them cheap at a local restaurant supply store.

Also try adding unsweetened soy milk, or Soy Slender brand which is splenda sweetened and comes in vanilla, chocolate and cappucino flavors.