Ebay is a good way to buy stuff, but if you can get a local authorized shop to match or beat the price then go to the shop. Between Alpine and Pioneer and Eclipse, they are all great companies, compare the features that each one provides that is within your budget.
IMO the Pioneer is going to give you the most bang for your buck but you might like the look of Alpine or Eclipse better.
My suggestion is the Pioneer Premier Deh-p860MP
http://www.pioneerelectronics.com/pn...etailComponent
http://cgi.ebay.com/ws/eBayISAPI.dll...739831251&rd=1
As for the rest of the system depending on how much you want to spend there is so many choices. Usually it is best to listen to what you're going to buy and read reviews and do some research.
I have been looking at the stuff from Elemental Designs lately. They seem to be a quality product at an awesome price.
www.edesignaudio.com
www.carreview.com is a great site to see owner reviews.