Question about computer anti-virus/malware (please see details inside).

So, I’ve been reading in the anti-virus/malware forums, and I’m confused. On the one hand, it seems that there are dozens of bad guy-types, from viruses, Trojan horses, spyware, spam, adware, to URL hijackers/redirecters, keystroke recorders, ransomware, and more.

On the other hand, there are a myriad products designed to fight the bad guys. But which product fights what? I want the maximum protection for my computer (within reason). What types of products (i.e., product categories) do I need, and what is the best one in each category?

Another concern is that some of these crime fighters are not compatible with each other! I understand, for example, that it is not advisable to have 2 anti-virus programs running at the same time, as they might see each other as viruses. So, which types of products CAN/SHOULD I run together? An anti-virus, and anti-malware, and an anti-spyware?

Can you help me?