Hey Andy, I just got an N9 last month and I love it!
I'll just post here the stuff I got and removed in case you need it.
Firefox- always a good idea to have an extra browser at hand. Opera is good too, but I mostly use the default browser.
Torrential- Download files through torrents and stuff, haven't actually good time to test it, but always nice to know you can download through torrents
Meecast- In my opinion its better than the default weather application. you can post the weather icon on the standby screen and the lock screen, really nice UI too.
Billboard- recently got it, and its just an extra UI application. You can add text to the standby screen, including updating; time, date, profiles, internet connection. you can even add your own stuff to the screen.
Drop cache- it frees up Ram by killing not needed processes.
Battery Usage- can check how much of your battery is used up in idle mode, or by other applications
FBreader- ebook reader
wazzap- whatsapp
Homescreen setttings- someone already posted it really cool.
Filebox- File manager for the N9

Now let me post some mods or tweaks that i have.
Status Menu Extensions by Coderus
http://talk.maemo.org/showthread.php?t=85816

Another mod that is related to the status menu
Unrestriced-System-UI
http://talk.maemo.org/showthread.php?p=1214016
its sub-mods
http://talk.maemo.org/showthread.php?t=85502
http://talk.maemo.org/showthread.php?t=84725

Fastern9
http://talk.maemo.org/showpost.php?p...&postcount=409
This post has the latest version I think, 0.9.7.

and ofcourse before everything you should get Inception. allows more modifications for the N9.
http://talk.maemo.org/showthread.php?t=85238

Hope I helped

Edit: forgot about Nitdroid!!!
http://forum.nitdroid.com/index.php?topic=241.0
that link will tell you about the installation of android.