Gateron Milky Yellows are extremely popular within the community for a reason. They're excellent linear switches, and extremely affordable. A little lube, and some films will make these perfect for any build. 

Switches are sold in packs of 10.
 
Quantity 1 = 10 switches.
 
Specifications:
Lubed With Krytox 205G0
Linear
4.0mm travel
50g actuation
5 pin