Some of you are probably a little confused over me including the Nexus One in the list of new additions, but the latest root method allowed you to root your phone and make it much harder for HTC to see if your phone is rooted or not, should you need to ever send it in for repairs or replacement. Unfortunately, as of me writing this story, the method to root the phone has been removed from the XDA-Developer site, pending a new method that is more reliable.
Here is eugene373's method to root the myTouch 3G Slide taken from XDA-Developers.
A method to root the HTC Aria thanks to attn1 and others can also be found on XDA-Developers.
Bin4ry posted evidence of the Xperia X10 being rooted on XDA-Developers as well, and information on how to do it yourself should be available soon.
LeshaK from samdroid.net posted up his method for rooting the Samsung Galaxy S, but mentions the high risk involved with his method and makes clear that readers should only try the method if they know exactly what to do. Even stranger is that he apparently doesn't even have a copy of the phone to try it out himself.
Image from AndroidCentral