I'm definitely investing in one of those when I'm back home. Not sure where I'm going to fit it though...
i would recommend AGAINST getting a treadmill for home
once you get one in your home you'll soon realise that staring at the same patch of wall (or even TV, DVD, whatever) is boring beyond belief. plus you won't be feeling like signing back up at the gym cause you spent $1000+ on a treadmill at home already!
i used to use my housemate's treadmill during magpie season and it drove me insane with boredom. i went through every DVD in the house in about 2 weeks.
remember, the only thing that catches more dust than a treadmill is...2 treadmills? hah i dunno, the joke kinda died before it finished
also nicole: my knees are pretty screwed too, so i got myself a knee brace. seems to have fixed them enough that i dont actually need it every time. you've probably already thought of that, but just in case...