Any of the mid-range Alpine decks are great. If he wants iPod, I'd suggest looking for one with full speed iPod interface. The older one's which require a special interface unit are really hard to navigate.
I put a lot of stuff from
www.woofersetc.com and
www.onlinecarstereo.com. They usually have great deals and quick shipping. Their pricing on the decks are decent. Their pricing on speakers and amps are killer.
If you are still deciding on a sub, I'd suggest the JL Audio 10W3v2. I just put one in my boat, and it sounds amazing. It only needs a .65 cubic inch box, so very little space. My box is 18" x 11" x 9". These can be had at the above sites for around $150.
My only suggestion for amps is look at the size of the amp. I didn't do this, and the amps I picked up where huge. I still love them, but they required a lot of space.