I've personally always stuck with Alpine gear. Can't go wrong, even the entry level stuff is good.

I had a double din HU, came with all the luxuries but it was like $1100. Was awesome though, never had a moment where I wanted something else. It literally did everything.

As for sub's, you need to work out how much space you're willing to sacrifice etc. My car has a custom enclosure built in which I will eventually remove as it looks f**king heavy, takes up space and even with dynamat it rattles like crazy.

A solid base is a decent HU with all the features, quality 4 channel amp, some dynamatting in door and a quality set of splits. You'll be happy with that...for a while anyway.