I have a Specialized Allez Elite setup up for tri with Syntace bullhorns and aerobars. I have my seat set forward between about what would be considered a standard road and tri position. I find this gives me the best of both worlds. While in a aero position, my hamstrings still get activated to a large degree, but on just longer "road" rides, I'm still in a comfortable position up on the horns. Actually, the position on the horns is exactly the same as it would be on the hoods of a road bike.
Eventually when you get serious, you'll probably end up with two bikes. Until now, get the most bang for your buck and get a good road bike. It can do both really well. This is the my opinion based on a lot of research and talking to athletes who've been doing this for some time.