Thanks to Nokia (and whoever has recommended me), I finally got the once-in-a-lifetime developer-discounted N800. After a little problem with payment and delivery, which fortunately were solved, I can enjoy this cute little gadget.
Using this N800 on and off for some weeks, I can only say that it's a great experience. On the hardware side, everything works perfectly. The 4.1-inches display is sharp, touch screen works without glitch, control buttons are easy to use, my 2 GB SD-card is detected without hassle, FM radio shows no problem, the "hidden" web cam gives good image quality. Speaking of web cam, the direction is a bit strange because it is rather "tilted aways" from your face. When doing a video chat, your partner would see it as if you don't face him directly.
Internet connection with both Bluetooth/GPRS and WiFi works out of the box. For road warrior with e.g. GPRS flat-rate, N800 is better than small-screen smartphone and surely lighter than sub-notebook. The installed Opera browser is good enough for most surfing needs, even Flash is supported, although YouTube video playback will be sluggish. Fortunately, playing typical audio and video files are smooth enough (hardware decoding, I reckon). Text, voice and video chat are all easy to setup and they work right away.
Since N800 is targeted as Internet Tablet, only few other applications are available preinstalled. This is a bit pity, as I guess this device could be a very good PDA. However, installing 3rd-party applications is not so difficult, e.g. browse to http://downloads.maemo.org and use the single-click install button. And there's Pimlico project to bring PIM suite to N800.
For multimedia, the included media player is good enough, but nothing beats Canola (see it in action) if you want to impress your friends, it transforms N800 into a portable FrontRow-style media center. With N800's speaker, Canola definitely boosts the "cool factor" easily.
When finally I can have some more free time (read: after finishing the dissertation), I want to play around with it and probably try to port some of my personal programs to the platform.