What is the best speaker for a car? And MP3/CD Deck for a car?

Eventually when I get my main car, I want to get great speakers for my car. I know BestBuy sells most of the speakers for cars. But i'm wondering what good speakers for cars are. Not the brand but what the Best Features are for car speakers. I would also need to get a iPod/iPhone-Ready CD Deck, so I also need to know good brands and features for that.

Check crutchfield.com. Anything Best Buy or Crutchfield sells is going to be top notch.

Get a Pioneer HU.
Get some RF speakers and tweeters.

There's no "special feature" you should be looking for on car speakers. Your clue is going to be the price tag. You get what you pay for in this industry. There's no secret speaker that nobody knows about which costs half but performs twice as good as any other. The best stuff Best Buy sells is going to be the Polk Dxi line, Alpine Type-S line, or Kicker's stuff. Sony, JVC, and Kenwood's speakers are junk. Go in and listen to them all. Buy whichever sounds best to you. If you can afford more than what they offer in-store, tell them. They have 5 times the inventory online and can order you higher-end versions of what you're listening to in-store.

A USB port is common on even inexpensive decks these days. Just plug your iPhone in via USB and it'll do everything else for you. Decide if you want Bluetooth or not. Bluetooth will allow you to make and receive calls handsfree and also allow you to stream music wireless (though the sound quality suffers compared to USB). Pioneer or Alpine.