Should I build a PC or buy a laptop?

My budget is just under 600 dollars. So around 580-590

Now what I don't like about most PC builds is that NONE of them mention the operating system. Like you can't use your new computer unless you buy a 100 dollar operating system.

I like the PC bundles on Newegg.com that match my budget, but again… No Windows with it.

If you think I should build a PC I would appreciate if you could help me with the part selection.
-Motherboard
-CPU (Really like the AMD FX-6300)
-Graphics Card
-Hard Drive
-Memory
-Operating System
-Power supply
(I think that's all)

The computer will be used for games like Minecraft, TF2, Terraria, League of Legends, and possibly Dota 2.

Added (1). Nevermind about the budget.

MY BUDGET IS 600 DOLLARS
SIX HUNDRED DOLLARS
$600

Visit this USA website and look at their bare bone systems

Self build barebone systems
http://tigerdirect.com

check this one out intel i7 @ $530.00
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=8511882&CatId=2628

Go here for the free up to date operating systems
http://distrowatch.com

You should build a pc. Its best to use recycled materials, like old window frames, old microwave ovens, and old smoke alarms. There's no wrong way to do it, just start disassembling, then solder it all together and your done. Enjoy your new pc