Um.... You obviously have not see a new 22" lcd have you? They look fantastic, why would you use a 15" that is so IBM PS/2 size. Get with the program, you aren't shopping for a car waiting for the Hybrids to get cheaper and really take off. It's just a monitor. Sure there is new technology coming out in the furture but when is there not.
So to answer your question... YES! I would buy one now. I went from a 17" to a 22" and you never want to go bat to those tiny little displays, it sucks gaming and even for just general desktop work.