Which of the bandit clans do you enjoy fighting the most? For those that don't remember the clans:

• Ghost Clan
  
• Wasted Clan
  
• Shrouded Clan
  
• Gearhead Clan
  
• Jackal Clan

The Wasted clan is my personal favorite. Combat with them is interesting because:

• They are encountered before you have enough weapons/bots/tools to easily get past anything you fight.
  
• They have a good assortment of weapons (including grenades) whenever they're encountered. IE Ghosts are usually either a full room of melee guys or vice versa, Shrouded guys never go melee, etc.
  
• Helmets but no armor makes choosing whether to go for a headshot debatable, whereas it's almost always worth it against everyone else.
  
• They have a tough, memorable boss.

All of them have pros and cons, though.