I was searching for Psion 3 and 5 series devices on internet because I have heard about them a lot and probably maybe saw one when I was a kid, and its amazing that a lot of devices from 90s are still functional and you can get your hands on them.
As its already said if you solder the usb port before it breaks, and dont drop N900 much i think it should be easily useable. On the software side its interesting to see that people keep on making new software for N900, Cant say how the web changes and how long the default microb keeps serving us.
I have dropped N900 a lot, I got it in december 2009, and just last month in August it fell from my computer table while it was hooked to the usb cable and now its microusb connector has problems, it didnt come out but it doesnt charge anymore unless I put some pressure on it while connected. I am planning to fix it myself, I am even planning to buy another n900 second hand but in good condition if I find it, I heard its available for very low prices.