Good depends on what your ears like and what you are willing to spend.
Lots of the same major players are still there today, but you can really find a lot of quality stuff at all price points.
For my ears, when it comes to speakers, nothing sounds better than Focals. And with Focal you can spend less than $200 or $1,000 or more on a pair depending on what you get from their line. But truth is you will find speakers you are happy with best by listening yourself. Just about ANYTHING is better than the crap that comes from the factory.
The same statement can be made on subs, depends on what you want it to do and how it sounds for your ears as well as how much money your willing to spend.
Alpine and Pioneer are making top notch head units still.
JL Audio, Alpine, Arc Audio, and many others make quality amps. The big with amps is getting "Class D" amps, they are super small, run very cool, and very efficient. Drive lots of power in a tiny package, they can even be mounted upside with no worries about overheating.