Hate drawing backgrounds? If you're like me then this nifty software will make it enjoyable!
http://www.sketchup.com/

Comic Pro's like Joe Quesada and Leinil Yu are beginning to use it in their work with stunning results!
Check out Leinil Yu's deviantart page for a behind the scenes look
http://www.deviantart.com/deviation/52891040/http://www.deviantart.com/deviation/52955441/I'm using it for the project im working on and building the environments has been really fun. Download it, it's free try it out and i swear you'll love it.
And to get you started with a few models download some from the Google 3D Warehouse TONS of stuff there, from Death Stars to sports cars
http://sketchup.google.com/3dwarehouse/