In my experience the most critical characters are leaders and investigators.
Leaders i define as someone who can identify clues and organize what to research and preferably have some contacts to fill in gaps in the PC's ability. Frequently they are high charisma characters and a silly high negotiation pool can make gear more available when lifestyle is spent on gear acquisition.
Investigators can come in a variety of flavors: Mages with detection spells (Detect Explosive, Passenger-Ranged, Spatial Sense-Extended Range, Analyze Truth, Area Thought Recognition, Mind Probe) or Technomancers (Tutor Sprites, Skinlink Echo, Multiprocessing/Mesh Reality) or Face characters with goodly knowledge skills or Riggers (with drones with a ton of sensors averaging a high sensor rating, high perception skill, multiprocessing if TM or Adept-Rigger with the equivalent of multiprocessing), etc.
For combat ability AFTER character creation SnS is good but Gel Rounds with DMSO and Narcojet are even better except against vehicles. Some jobs just need trolls or burst-firing .50 cal sniper rifles with AV ammo.
I agree with playing whatever is fun but if you are going in totally blind and dont care what you play an investigator drives story and a leader helps the team be more effective provided you are likable enough they are down with being led.
My 2 nuyen