My 10-year old N900 is still my main phone - and I have spare ones in case this original breaks but it seems really unlikely, even battery is original one.

Overclock with custom profile, swap offload on sd card with flopswap, phone, sms, calendar, mail, GPS with modRana, public transport with Fahrplan (CH SBB), podcasts with gPodder and 1.8x playing on SMPlayer, 3G modem with USB tethering, BackupMenu...

But today I have a new requirement to access a customer's VPN with Swisscom Mobile ID and I discover "SIM application toolkit" and that N900 has no support for it. With hope I may port MeeGo code: https://github.com/meego-tablet-ux/meego-app-satk