Interesting thing happened a couple days ago. My wife's Evo downloaded and applied a system update. After it rebooted, Swype kept force closing. I went into settings and disabled it and switched to the default keyboard.
Turns out the update gives you an official (non-beta) version of Swype, but it conflicts with the beta version if you have that installed. In order to fix it, you have to uninstall Swype, then reboot, and the official version should show up as an option.
As many of you know, Swype is a keyboard where you slide your finger across the letters instead of tapping (though you can still tap if you want; it's also used for entering words not in Swype's dictionary). The company that makes it has not released it to the public. Instead, you have to either get in on the beta or hope that your phone's manufacturer or carrier negotiates to have it preloaded. I guess in this case, HTC or Sprint must have just negotiated a deal to get Swype on the Evo.
Another good thing is if you are currently part of the beta, you can transfer your beta license to another device that doesn't have Swype included. So if you have a spare phone or want to give it to a friend or family member, that works too.