Chipping them is great an all, but once you get online with a modded xbox your xbox is scanned and you will then be banned for life (at least with that particular xbox, s/n) from xbox live. Hence you will have to purchase a whole new system to play online. I don't play many games anymore that aren't on live.. except for Splinter Cell... so for me that would suck big time.
PS. A good friend of mine works for Microsoft... they are aware of most if not all of the mods can be done to the xbox. Shit.. if you can find them online... I'm sure someone who is getting paid to find them will too. Already they have programs that scan your xbox, but in the next few months they are going to be locking it down tight. No more cheating online, you have probably already noticed... just a fair warning to anyone who tries to jump online with a modded xbox.