[null]

• Arch
  More barebones and fun. Once you configure it how you like you will be very cozy.
  
• Gentoo
  Just for fun.
  
• Debian
  Easier than Arch and still good
  
• Ubuntu
  Debian with unity and bloat
  
• Mint
  Debian with <insert de> and bloat
  

[Exkr]

There are some pretty interesting looking ones, which I think most are still beta or even alpha. Ozon OS, Evolve OS and Korora -- Which I think is actually stable now.

[Coca.]

Kali Linux. It is rumored that true hackers use it.

[FireStorm]

Kali Linux. It is rumored that true hackers use it.

[Skullmeat]

Arch or Debian. Both are really good.

[Jacket]

I've tried Debian, Kali and Ubuntu and I prefer Debian or Kali honestly. I haven't really used Linux much though. Load them in a VM and try different ones out.

[§herlock]

I have been using Arch Linux with cinnamon, it works great.