The N900 is still by far my favorite of all the phones I ever owned, and it was so for three main reasons.
Number one: The slide-out keyboard.
When I had that keyboard, the best email-interface was still just Mutt over a terminal. Which is to say, the best and most efficient email-interface ever! A single blind thumb-twitch to do any action at all.
You could use Vim! It actually made sense to use Vim. Without looking!
You could type without looking!
If I really needed to I could even use it to write code, though I never tried very hard coz it was still damned frustrating and proper keyboards are usually fairly nearby when it comes to thinking of spending hours on a task.
It was way better than a touch-screen for shelling in and fixing server issues when you’re stuck at a party away from keyboard. I’ve done it with a touch-screen, and even hacker-keyboard isn’t close to that physical-thumboard.
Actual code writing tends to mean using lots of symbols, and while the N900 keyboard was better than a touch screen, both make you want to rip open your skull and put the wires in directly in frustration.
I could and did use it to write and edit long-form prose. Modern screen-keyboards are no way to edit a novel!
It was ace.
Touch-screens are absolutely rubbish for text-input, and even good voice-dictation rubbish for text-editing.
I miss that keyboard so much.
I own a similarly sized Bluetooth keyboard now, but never seem to have it with me coz it’s not attached, and has no way to attach.
Number two: The microphone.
That phone had the best microphone out of any phone-mic I’ve ever owned by a clear mile too. Certainly the only one that could stand up to being used in the band practice-room without just distorting to hell coz of the volume.
I still use it for that now and then, for video-recording band-practise, cos nothing else ever came close. The USB port broke and now I can only transfer files with WI-FI and have to use an external battery charger. All my batteries are swelling slightly and really ought to be retired before they burn my flat down.
But I don’t have anything else that will actually work for that task.
Number Three: The Operating System
In particular, it’s operating system’s freeness and open sourciness and unixitude and native-bash!
It ran on a full Gnu/Linux system, with Bash and all the Gnu Tools and an X-11 server and all the free software goodness you could ever want.
Anyway, put me down as demanding a phone with a slide-out keyboard, a free-software based OS and an excellent microphone that won’t distort under extreme volumes.
Trouble is, these days it’ll also need an equivalent compatible to Daydream VR, a E-Reader that actual books can be ordered from (ideally without Amazon, but needing at least all Amzaon’s content), and some kind of Chromecast-a-like, plus access to the best geo-mapping available and Netflix-or-better.
Which means it’s unlikely to be the Plasma-Mobile, KDE-based indy phone OS ( https://plasma-mobile.org/ ).
Much as that fact makes me sad, because I really miss all those features and I find I’m regressing on the open/free software front quite badly. I even have Windows in my life again now for VR reasons, despite it being Microsoft’s damned fault that Nokia’s N900 system died.
Bonus Number
It even had a built-in kick-stand FFS!