Based on your needs and what you have, I'd stick with what you got. Seriously, a $250+ purchase just to use some damn blue-tooth headphones, that's just crazy.

For one I would never consider a PSPGo over a PSP3000 and I would only choose a PSP/DS over an iTouch if you actually want to play games. Otherwise, I'd sell the 3000 and buy a iTouch.

how is the psp for listening to music ??? it easy to start shut of or does it take a while ?

From what I've read, the PSPGo offers no real advantage if you already have a PSP so I would just go with the iPod.

Also, pretty much what SuperChunk said about the headphones.

-edit-

I've seen a few people mention this and I have a question for you-- where do you put the PSP while you're using the DS3?

Ipod Touch by FAR

you have a 3000, and you probs dont need to carry both around the hole time

you have never had an ipod? i may die without one lol

If you don't want to carry two devices around, the only logical thing to do is to sell the 3000 and buy the go. While the GO can compare to the ipod touch for music, the touch is nowhere close the the psp for games. I personally find both devices to be too damn expensive for what you get.