It's always hard to determine when is the right time to upgrade our AV gears as the world is changing rapidly
This year SONY SXRD (Silicon X-tal Reflective Display) has taken the world by storm. After a year or two, perhaps the new generation of high-quality large flat-screen display, the SED (Surface-conduction Electron-emitter Display) may take over SONY or the possibility of a new manufacturer may even invent a totally new superior technology, etc. Just like VHS to VCD to DVD and now to HD DVD/BD. In a few more years, another new higher definition media could emerge....it never ends
Hence, probably there's no right or wrong time to upgrade our AV equips as long as we've taken every reasonable step to ensure our investments are protected or at least will not become obsolete way too fast say within the next 5 years...(eh this is too conservative noh)
For HDTV nowdays, most of the concerned issues are iron out while early adopters of either HD DVD or BD players are certainly facing much higher risks. The water is too hot to take a dip?