You want simple, I installed a JVC KD-AHD79
. It works great with an iPhone. Plug the iPhone into the USB port and choose how you want the receiver and iPhone to interact. You can have the JVC control the iPhone or you can have the iPhone control the JVC (my preference). It also has an aux input on the back that can be used for Bluetooth or sound input (It's labeled BT AUDIO when you're switching sources) that I use for the sound from my television, and another aux on the front under the USB port. The sources can be easily switched using the remote which also has volume controls and a mute.
I said it was simple. You absolutely will have to read the manual
, though. More than once, and keep it handy for reference. Rather than deal with keeping up with the paper manual, I keep a pdf version handy on my computer. It's searchable, and it's doesn't gather dust. ( I've attached a copy if you're interested.) I don't think that the need to read the manual is unique to this unit. Modern receivers do so much that you'll never figure everything out on your own, and you'll miss features you might enjoy.
The KD-AHD79 has some other nice features, such as user selectable display colors and built-in HD radio tuner. (HD stands for Hybrid Digital, not High Definition, and yes it really sounds better―and it's free)
I got my KD-AHD79 from Crutchfield
, and they're on sale right now for $129.99, $50 less than when I bought. Competitive price, but there was another reason, Crutchfield has a program where you can trade-in old stuff
, such as my original iPhone, for credit. In April, 2011, I got $90.80 credit for my original iPhone without giving them the charger. If you're thinking about trading up, iPhone wise, you could come out paying very little for this (or a different) stereo there.