I like the GAIA project for Microlensing: (If we're going to go out there it would help to know where). I also really like the mapping ESA did with Mars.
http://gaia.esa.int/science-e/www/area/index.cfm?fareaid=26

I am interested in The Spaceeward foundation for more independant type projects:
http://www.spaceward.org/

They are doing the elevator 2010 project:
http://www.elevator2010.org/site/index.html

Remote robotic assemnbly:
http://www.spaceward.org/rra.html

Obviously nano or any tech isn't totally perfect. Some people are selling it for more then it's worth; but the space elevator seems OK so far... Entropy makes sense.
I think inventing ant-gravity is important for most of this and extreme health break-throughs. Any of this type of extreme activity is going to require more rugged humans.