Stevia's good.
I like Teas, and lots that I go for are naturally caffeine free: Moroccan Mint; Redbush; White tea with Jasmine; Chai.
I also went through a cocoa phase. Making it with a generous amount of good quality cocoa, stevia to sweeten (add at the end - it doesn't like being simmered); vanilla and a touch of chilli, ginger and cinnamon.
Lots of people seem to love coconut milk / water - I think it's vile - but might be worth a try.
For a cold drink I like ginger ale with added root ginger and lots of fresh mint leaves (crushed slightly to release the aroma), and a generous squeeze of lime.