I can set Text tones via CustomSMS. Emails can be set via Gmail and the Email apps i have. Ringtones for calls are set by the Contact area. I can also change the default notification for each as well as setup a custom one for each person. The benefit of CustomSMS, i dont have to use their program. I still use my normal text messaging app to send and receive messages. I dont have to disable the one already built in and use Handcent. That is the only reason why i suggest that app. It is only $1 to get for unlimited number of contacts. That isnt a bad price for such an app. Not trying to mock Handcent, i know a lot of people use it. Just saying customSMS already works with what you have.
The reason why I use Handcent over the default messaging app is for the themes. I do not like the GUI of the default app. If I could change that I would probably go back to using it. I haven't looked into actually changing the themes, or if it's possible, but if I knew it could, and knew how to change it. I would stop using Handcent.