These is no rule that says the best cocktails have to be completely complicated and contrived. I'll take a Belini, Vodka Tonic, or Cuba Libra any day.
A fantastic base for a simple cocktail is prosecco, cava, or champagne (all are kinds of sparkling wine...just from different countries). They've given us the mimosa, belini, and kir royale just to name a few. And here's a great idea that I recently read in Instyle Magazine. Add a single vanilla bean to a glass of the bubbly for a decadent infusion of flavor. Doesn't that just sound amazing? And the best thing about the vanilla bean is that there is no need to switch it out between glasses. The potency will remain even after you refill your glass several times. Salut!