1) Z77 and Z87 are motherboard chipset types for Socket LGA 1155 and LGA 1150 respectively.
You can not use Haswell CPU (LGA 1150) on Z77 socket so you have to buy Z87 one.
Similarly if you go for Sandy Bridge or Ivy Bridge you have to buy Z77 chipset motherboard.
2) Sabertooth is too expensive and does not manage heat well. Not recommended. Get ASRock Z87 Extreme4 Motherboard. It has won many awards due to its sheer durability and reliability. It would be best for you and is cheaper too.
3) More than 8 GB is not needed for gaming PC. Get 8 GB variant if you are building a gaming PC of same company.
4) Buy Sandisk Extreme II SSD instead of that one, its faster and overall better.
5) Monitor is too expensive, you can cut out on that. A good Full HD Monitor should not cross $200 (£150) budget.
6) If possible drop that keyboard mouse combo. They are too expensive and do not contribute anything towards performance. You are better off with any decent mechanical keyboard / mouse wireless combo. It would be better I believe.
7) Get Fractal Design R4 Black Pearl Case. The case has best noise suppression, cooling and cable management facilities. It stays very quiet and very cool and is the best Mid Tower ATX case you can think of. After that you have Corsair 400R but the R4 is advised.