I've noticed that motherboards have different PCI express slots. The most common is the x16. What would be an example of an x1 or x2 or x4 or x8 or x32 PCI express card? Should I look for motherboards that only have x16 PCI express slots?
Raid cards, audio cards, network cards, etc etc etc
"Should I look for motherboards that only have x16 PCI express slots?" it depends what you want and what you will want in the future as to what expansion slots you have. I personally haive only ever used teh x16 for a GPU, as i use on board audio and nic, and dont have a raid card or any other type of add in card.