Maemo 5, Reviewed In Depth

"This write up will focus primarily on the software department of the N900, as well as its capabilities (by the way, another phone in this line-up, set to launch during summer 2010, won't differ from the N900 in terms of hardware). And the best way to break down an OS is to run through every feature an app it has got on board."

I used an N800 with an older version of Maemo for a while prior to moving to the iPod Touch.  Nokia has done a fine job with the OS and being mostly open source gives it an advantage over the some of the more popular mobile OS's.  If you've never had a chance to play with a Maemo device, this review is a great starting point.  If you are on a mobile device you might want to wait to take a look at this review as it has a HUGE number of screen shots.