Since the Q10 has an AMOLED screen on it, I wanted a completely black background on mine to maximize battery life. Here's the PNG if you'd like to save it and do the same:
http://forward-thinking.net/BlackOut.png
Get your old BBOS ringtones back :
Missing those classic ringtones from your old BlackBerry? Here's how you can get them on BlackBerry 10 | CrackBerry.com
Don't forget those keyboard shortcuts! 'T' = Go to top of list, 'B' = Go to bottom of list, 'SPACE' to scroll down by 1 page, etc. This is one of the primary reasons I waited for the Q10, the accessibility benefits can't be overstated enough here!
Get some Android apps sideloaded up, it really helps with some of the big name apps missing from app world. A few apps I've installed on my Q10 are: Amazon Kindle, AndroIRC, Flipboard, Google Maps, Netflix, Trillian, Words With Friends, Youmail. There's plenty of tutorials around on how to do it, and many of these android apps work great on the Q10!
Those are just a few off the top of my head...