[Insatiable]

You can do the above. And change the settings in each app your wanting the diff notification for. If you are looking to have diff text and ring tones for each contact...

For example -
Song 1 plays as a text when my gf texts me, Song 2 plays if she calls
Everyone else defaults
Song 3 is for my moms texts, etc.

Then use Ringo Lite in the market place. Sometimes it will default you back to a reg tone, I haven't figured out why, its not often so its just a lil buggy, but that will assign diff tones to each contact for calls and sms.