For total control of your xbox360 go for jtah/rgh... it allows you to play games from usb/hdd and you can run unsigned codes for homebrew and modding games etc... but it is a pain in the ass to fix yourself :/
Xk3y: Is a solderless device that you connect between your dvd drive and motherboard ( very easy to install... what it basiclyy does it that it emulates your dvd drive allowing you to play games from hdd or usb thumb drive
No need for flashing or modding its almost just plug and play
only donwside is that you have to exctract the dvd key :/ But if you want it the easy way go get a wasabi360... it is also an emulator but with esata instead of usb and it has a buily in dvd key exctraction
Only downside on this one is that you need to cut a little hole in the metal cage of the xbox :/
So there you go, hope it helped you
If you have anymore questions juat ask me