As far as science goes, the better-faster-cheaper ethos NASA had with the Mars Rovers should be revived. Robots are a terrific way to get actual science done. That said, the lessons learned from building and working on the ISS would be a good starting point for creating a vehicle to take people to Mars - a place we can eventually make habitable (http://www.users.globalnet.co.uk/~mfogg/zubrin.htm).