Welcome to the endlessly fun toy that is the N900!

As this is a very open machine, there are many, many ways to use this device to its fullest. Personally, I'm still using the stock kernel and PR1.3.1 release of Maemo. (I'm still having way too much fun writing apps for the thing to bother with keeping up with the CSSU folks.)

But yes, there have been many good updates since the untimely death of Nokia. If you want a quick and easy summary of many of the best updates, here's a good link to get you started:

N900: The Perfect Setup

Edit: oops, gianko beat me to it.