I Mod and sell xboxes for spare cash in my free time. On all my xboxes I include these Emulators, as they work flawlessly on my xbox.
286-386 - DOSXBox
Amstrad CPC - ArnoldX
Arcade - MAMEoX128 Plus!
Atari 2600 - Z26X
Atari 800-5200-130-320-XL-XE - AtariXLBox
Atari Lynx - Mednafenx-lynx
Atari ST - WinstonX
MSX-MSX2-MSX2+ - BlueMSXBox
Neogeo-CPS1-CPS2 - FBAXXX Pro
Nintendo 64 - Surreal 64xxx
Nintendo GB-GBC-GBA - XBoyAdvance
Nintendo NES - Mednafenx-nes
Sega Genesis-32X-CD - NeoGenesis
Sega MS-GG-SG-1000-SC-3000-SF-7000-MK3 - MekaX
SNK NeoGeo Pocket - NeoPopX
Sony Playstation - PCSXBox
Super Nintendo Entertainment System - xSnes9x
Turbo Grafx 16-PCE-SGrafx-CD-SCD - Mednafenx-pce
Wonderswan - WonderSwanX
X68000 - X68000X
Oh yea and Can't forget MameOX for running all those nifty MAME roms too
If you want to download them here is a link to the torrent.... http://www.demonoid.com/files/details/306993/4336113/
As for the Roms, well if you watch the newsgroups at least once a week or so, someone will post every single rom for whatever system.
I have pretty much all of them on mine.
BlackTree you would need to load and run XBMC XBox Media Center.
It will allow you to view pretty much any movie format on your TV, as well as play pretty well any type of music file. You can either serve the files to it via another PC, or if you have a larger HD in your Xbox, Store them on the Xbox. The newest versions of XBMC will also play shoutcasts and podcasts. Plus you could install LynxBox and surf the web from it as well
Here is a link to a rather descent compile of the latest XBMC ....http://www.demonoid.com/files/details/420191/1445371/
[This message has been edited by 8Ball (edited 08-19-2006).]