Is there any other mp3 players that can hook up to the D3, preferably through the bus in theback so i dont have to see it. Im looking to buy a new one and was wondering if i need to go with an ipod to get the ease of use and whatnot with the d3.

Nope. Only the ipod. Anything else would have to connect through an AV input and use it's own controls.

can you use the navi AND listen to the ipod at the same time? sorry for being a bit off topic

Yes you can.