Once again, Sony makes us reconsider what PDAs are all about. The Clié PEG-UX50 ($700 street), billed not as a PDA but as a PEO (personal entertainment organizer), combines a digital camera, an MP3 player, a thumb-style keyboard, and two flavors of wireless connectivity for entertainment and communications. The landscape screen-which makes the unit look like a doll-size laptop-really shows off Sony's superior interface for the Palm OS. Yet even with all its features and software, the question is: Should you spend $700 for a personal entertainment device? We vote yes.