Here are some tips (from a very seasoned console owner, who also has a 360!):
You pretty much don't
need anything additional. It comes with everything you need to get started right out of the box. However:
- The wireless controller does indeed use batteries, but 2 come in the box. (Note that the guide states that (paraphrasing) "for best use, do not use rechargeable batteries"). You can spend more money and buy a rechargeable battery pack and "play and charge kit" (which actually charges the aforementioned battery pack) [editorializing: which, incidentally, comes with the PS3 controllers for free. *ahem*] if you don't want to always buy batteries.
- If you want 5.1 digital sound, you'll need to buy a toslink (optical) cable. (You won't need this if your home theatre receiver has HDMI inputs... but see below: )
- If you have an HDMI input on your TV (and/or home theatre receiver) and want to use it (it's not necessary, as the Xbox does come with component cables), you'll need to buy an HDMI cable.
- If you want to use your wireless network, you'll need to buy a wireless adapter [more editorializing: PS3 does that out of the box, too].
- Yes, the 360 can play a good number (but not all) of the original Xbox games. Go here:
http://www.xbox.com/en-US/games/backwardcompatibilitygameslist.htm to see the list of games. (Both Halo and Halo 2 work, BTW.)
Hope that helps!