The DX is my first Android phone and after getting the 2.2 OTA update i rooted. I got the standard root apps, barnacle, drocap, addfree and titanium backup. But what else can i do? What are you doing with your DX with SU permissions?
You could also try SetCPU and AutoKiller to make your phone more efficient and give you greater battery life. Keep in mind that rooting doesn't give you super powers or let you travel through time, it just gives you a little more control over how it functions...very useful, but it doesn't change the world.
If you have or upgrade to the paid version of Titanium, you can freeze bloat ware apps so they wont launch themselves in the background and use some of your phones resources.