iPhone Accessories I'd Love to Have

I found a lot of iphone accessories that I need. I haven't really enjoyed my iPhone that much because I didn't have all the accessories that I needed. For one, I cannot even use it to listen to music while I'm in the car. I need to buy this accessory that would allow me to listen and at the same time charge my iPhone. Oh there's also one accessory I found which I think the whole family will enjoy. It's the headphone splitter and I'm gonna buy one. Now the problem is, whose iPod or iPhone should we use?