From what you describe in your question I think you're looking for three tools hardinfo, synaptic, and galternatives.
hardinfo allows you to see all your hardware and even do a few benchmarks.
sudo apt-get install hardinfo
synaptic gives you a list of software, that can be searched, and sorted by category. It also allows you to install/uninstall and manage software.
sudo apt-get install synaptic
galternatives allows you manage and select the default package to provide a specific service, such as specifying the default version of java to be used.
sudo apt-get install galternatives