First is putting on a more user friendly dash. I prefer an older version of XBMC with the MC360 skin. I think the newer versions of XBMC are a bit more style over substance.
Fantasy football team name + The Sacko for some smack talk.
There's a few different ways to get XBMC as your main dash. A more popular option is to set it up with a shortcut XBE that will change boot priority for dashes, but I just deleted UnleashX and dropped XBMC in. I figure this leaves less room for error and I felt ballsy enough to do it since I had XboxHDM running anyways. If you don't have XboxHDM and your EEPROM, you probably shouldn't do that just because you'll be screwed if you mess it up.
I left UnleashX on the Xbox and put it in the applications folder. UnleashX is a good way to rip games, so it's a useful dash to keep around. Honestly, there's not a whole lot UnleashX can do that XBMC can't if your Xbox is only softmodded. So, I ripped all of my Xbox games with UnleashX which did not take too long (probably averaged out to about 12 minutes per game, much better than ripping games to the PS2 HDD), and added about 30 more games which I downloaded.
If you're downloading games, you'll need to FTP them to the Xbox. Filezilla is a wonderful option for this. If you don't have a crossover cable then you can share your wi-fi connection through your ethernet port and connect your Xbox to your computer that way. You'll then be able to check the IP address in XBMC (or on the main screen in UnleashX) and start moving your games over.
I ended up putting 82 games on the Xbox. There was still a fair amount of free space as well, but I think I covered most of the Xbox essentials. I also put on quite a few emulators. This is a pretty good list of what's available.
These were the emulators I ended up putting on. There's a few MAME games, a full NeoGeo set, full Gameboy/Color/Advance sets, full SNES set, full NES set, full Genesis set and full 32X set. The Nintendo 64 emulator has about 100 of the games that work best with the emulator. After all of the games went on, there was still over 200gb left. Plenty of space to add more MAME games and get a healthy collection going for a PlayStation emulator, too. The NeoGenesis emulator is actually pretty cool, as it will run genuine Sega CD games from the Xbox's drive. Sort of a novelty thing, but I tried it out.
I also added DLC for all of the original Xbox games that had it and applied title updates as well. You can no longer download the title updates or the DLC since the original Xbox Live servers went offline, but some kind souls created installers with all of the content that you can download and run. They'll install the DLC and sign it to your console.
A lot of that content is multiplayer only... but all is not lost. Most multiplayer Xbox games had LAN options... which you can tunnel over the internet and play with other people. Enter XLink Kai and XBConnect. These let you tunnel that connection and play online. I use XLink Kai semi-frequently for Halo 2. This is the most common game people play, but I've managed to get people together to play some Tony Hawk 2x as well (awesome). I prefer XLink Kai's interface and the fact that it has a native OS X client. XBConnect has a much more serious crowd, which can sort of interrupt the fun of just getting online to play.
Anyways, this Xbox is done.
It needs to be cleaned though. A lot of consoles seem to favor these ridges in their design for some reason. Dust likes to sit in those ridges but it's not a problem.
I take a paper towel, wet it and then use a credit card to run it along the inside of the ridges to get the dust out.
Now it looks brand new and it's better than ever with a 500gb HDD and tons of games.
I traded this Xbox to my friend for a 120gb PlayStation 3 slim, Max Payne 3, Uncharted 3, Call of Duty: Ghosts, Sports Champions, two DualShock 3 controllers, two Move controllers and the PS3 camera. He was having issues with data becoming corrupted on the hard drive and didn't want to mess with fixing it, so he bought a PS4 and wanted a way to play some older games.
This Xbox was actually finished and the exchange was made a couple of weeks ago, so I'll have some PlayStation 3 stuff up soon.