The pick of the lot, at least for people like us would be NASA TV! It lives on Intelsat 701 3854R sr2000 FEC 3/4. This is a satellite over in the eastern sky for much of Australia. I love it and can watch it for hours until my bum is numb.
They have live broadcasts from ISS, spacewalks, interviews, Mars Rover reports, deep space reports, anything to do with aircraft, space and NASA. It's pretty much the same as the streamed video on their website but the quality on the TV is much better.
http://www.nasa.gov/multimedia/nasatv/
Just this afternoon I was watching interviews with the astronauts that are taking the return to flight shuttle mission and watching feeds as they transport the shuttle making it ready for launch.
I highly recommend this channel, I'm sure you guys would love it! Unfortunately it needs the biggest dish you can lay your hands on. 2.4 metres minimum but at times when they power share with data feeds it can require a larger dish.
They will no doubt have the next shuttle launch live.