I have the Powerbar 2: http://www.amazon.co.uk/Powerbar-as...F8&qid=1365418395&sr=8-1&keywords=power+bar+2
It's solid and barely leaves a mark on the door. Nothing major anyway.
Also the JML Iron Gym is a popular one, although I prefer the Powerbar 2 as it goes higher-- the actual bar is above the height of the door frame so better for taller folks.
For Bodyweight routines, you could check out Ross Enamait's website (Rosstraining.com). I haven't used it myself but it seems to be quite popular. I do bodyweight stuff at home: pullups, one arm pushups, handstands, and various things on rings which I attach to the pullup bar (dips, rows, levers etc). I also have a kettlebell which is pretty awesome for strength and conditioning and it allows you to do some intense cardio without going anywhere or jumping on a hamster machine. I'm loving kettlebell swings and Turkish getups at the moment.