The parts can be tweaked a little depending on your requirements and preferences (only you can determine this).
For example, if this PC build is going to be used purely for gaming, then an i5 should suffice. If you will be using this PC for multitasking/editing work, then an i7 would be better (due to hyperthreading). Then there is the question of you planning or not planning to overclock. Getting an overclockable CPU, you are required to purchase a good aftermarket CPU Cooler (either air cooling or liquid cooling, depends on you). A locked/non-overclocked CPU can do away with a stock cooler (but an affordable aftermarket cooler can also do you good in terms of temps).
The choice of storage type and capacity also plays into consideration. In my suggested builds above, I opted to get you a 500GB SSD. The SSD's are known for their faster read/write speeds as compared to the power-hungry, noisier and slower traditional HDDs. Though SSDs are generally more expensive for lesser capacity than HDD. A good idea, if you need a lot of storage capacity, is to pair a 250GB SSD (to be used for your OS, utilities, programs, and several games) with a 1TB or more HDD (to be used for general storage, files, and other games). The SSD will increase your boot times and loading times (but not much performance difference in most games, except for a slightly faster loading times for open-world type gaming).