X, like any other piece of software, is only worth the money if you have a compelling reason to use it. When the day comes where you say "oh man I need X to do Y..." you'll be ready for X.
The only thing that you can really get out of X that you can't get out of 9 is the ability to run *nix software like apache/php/mySQL. Quite a wiz-bang thing, but only if you actually have a use for it.
The touted benefits of stability, multithreading, and pre-emptive multitasking are more than offset by the complications introduced by the complexities of Classic. Classic is fine for occasionally starting up that relatively simple legacy application, but you don't want to spend your day with it. Stability, etc., are great underpinnings to an OS that you have a compelling reason to use, not a compelling reason in and of themselves.
While X now seems ready for prime time with X.1, most of the software isn't. Plus, if you think $130 is steep for an OS, just calculate the price tag of a full suite of X native applications.