One of the things folks really (really) like about Android 4.0 is the way you can disable system applications from the settings menu. It doesn't delete them, but it does keep them quiet and out of the way while perusing the app drawer. Anything that gives more control to the user is a good thing, and we're just as glad to see it as you guys are. Adios, City ID!
But for some apps, it makes very little Sense (pun intended, tip your waitress, try the veal) to try to zap them away -- especially core components of the operating system. HTC Sense 4.0, at least the software versions floating around of the One X and One S review units, has a couple listings that make you just want to try it. There's an entry called "phone" and an entry called "dialer". There's also two separate contacts apps listed, one is a measly 8k and the other is a measly 28k. Don't disable any of these unless you're sure about what you're doing. If you disable one of the contacts apps, your dialer and phone app stop working. If you disable the other, the whole phone UI resets. If you disable either the phone or dialer apk, let's just say that the debugger goes hawg wild (as opposed to normal hog wild) and things get a little wonky.
We're sure there's a rhyme and reason to what's going on with duplicate apps, and we have our guesses. But until devices ship with final software to folks who can take the time to look at them and play a bit, we're going to go on record and say don't disable the core Sense apps. Android hackers will soon build a list of what's safe to disable or delete, and what isn't. For now, if you've lain your hands on one of these beauties, enjoy it as-is. We are!