I've been a long term fan of PalmOS devices. Starting longer ago that I care to admit with the original 'geek tool' - a first generation Palm Pilot. Various mishaps and new toy frenzies later I was lured from the, then moribund, Palm hardware to the new Sony Clies - first an NR70V and then a UX50. Sadly the OS itself was lagging behind both the Symbian Smart Phone implementations and capabilities of the Microsoft PocketPC platform while Palm tried to work out if a dual OS strategy (smart phones and PDAs) was the way to go, or if a rebuild based on BeOS or a port of the API onto a Linux core was the winning direction.
A resurgence in Palms design team, coupled with a realisation that the platform had stagnated seems to have been the final nail in the coffin (although for most of us having Sony drop the non-Japanese products was more of a blow) with no hope of a return to the market (at least with PalmOS, although a Symbian based joint strategy with Sony Ericsson isn't too unbelievable.
I hope for Palms sake they pull something more impressive than the Treo 650 or current Tungsten/Zire models out of the hat or the PDA market may be subsumed into smart phones faster than expected...
Update (September 2005): PalmSource is history. Wonder how long before the first Windows Mobile based Treo ships !