PCI Express Questions

I am planning to build a gaming PC/HTPC for about $2,000 early next year with either an Ivy Bridge or Haswell Intel i5 CPU without overclocking. After looking at the various prices and features for motherboards from both Asus and Gigabyte, I would like to ask which PCI Express slots and connections I should choose for the various expansion cards that I plan to connect to the motherboard. I am not certain if I have all of the PCI categories correctly listed, but my understanding is there are: PCI Express (x1 and x16), PCI Express 1.0 (x1 and x16), PCI Express 2.0 (x1 and x16), and PCI Express 3.0 (x1 and x16). With the following items listed, which PCI Express would work best?

1. Video Card (Connected to a 1080P HDTV via HDMI)

2. Sound Card (THX certified Creative sound card with RCA audio plugs)

3. WiFi card

4. USB 2.0 or USB 3.0 expansion card (if motherboard does not have a sufficient number of USB ports available)