Haven't had the chance to post a reply here. I'm new too and bought a brand spanking new N900! I'm addicted for life. The smoothness, power, flow and UI are spectacular. And it's getting even better!
Before that I was a heavy duty smartphone/PDA user.

My previous devices are:
Atari Portfolio (Very old skool), Palm III, Philips Velo 500 HandheldPC, Sony Clié NR70V, HP iPaq h2210, HTC Touch Dual, Sony Ericsson XPERIA X1. And I'm probably forgetting some stuff.

Cheers,

Bloke from the Netherlands