Chihuahuas are one of the longest living dog breeds. If you are looking for a long term playful partner then Chihuahua is certainly the best choice for you. They are ranked as healthiest among all dog breeds.
My dog loves coffee too! I found out the hard way that even a tiny bit or coffee is bad for a chiweenie though. Now she gets milk, a tiny bit of sugar, and just enough decaf to give it a coffee taste. She drinks her coffee beside me every weekend.