RDR definitely. The only reason why I would recommend MAfia 2 over RDR first is due to the fact that it's harder to find (Unless you go to Best Buy or Target) and the platinum Hits version comes with all 5 DLC packs which cost you about $9.99 each on Xbox Live. I highly recommend Mafia 2 as well. RDR is easily the best game this gen (As far as open world, then Skyrim and finally GTA IV + The Episodes).

Skyrim and Dragons Dogma are two games I would recommend to you. Forgot to add Dead Space 1 & 2 (If you liked Bioshock you should like this franchise as well).

If you can afford to, I would say abig resounding YES! Also make sure to get it with a 250 GB hard drive (Bundle). I would highly suggest it, only if you can afford to, if not then no. Stick with what you have.

I am a huge Breaking Bad fan myself, currently watching the latest season. I own both games and right now I prefer Skyrim over The Witcher 2 (The Witcher 2 has excellent graphics and a good story) but I am really loving Skyrim at the moment (You should also consider Dragons Dogma, I platted that in 3 weeks). I would go for Skyrim (Try to get the CE edition from Best Buy or Newegg.com first) then The Witcher 2 (Has a deeper learning curve for sure but is lush and beautifully looking). I definitely would recommend both for sure. The Witcher 2 was on sale for $29.99 at gamestop last week, not sure if the sale is still active or at all in your area still.