As the price rises for motherboards obviously the features increase, these features usually consist but are not limited to:
Extra ports on the motherboard including USB ports etc.
Extra PCI Express x16 slots (even if a motherboard has 2 PCI
Express slots they are not always able to work together in SLI or Crossfire) This is why you should always check if they support SLI or Crossfire if you actually want to have 2 GPU's working together
You will also see a change in quality, the high the price of course the better the quality as well as survivability, other things include more SATA ports and an increase in the amount of ram that can be installed as well as the MHz it can run at or the CPU's wattage support