I just recently beat the main questline Fallout 3 with a sharpshooter. He's already at level 24 and I will continue to do side quests until he reaches level 30. He uses all forms of combat, unarmed, melee, small guns, energy weapons, and big guns. This allows him to to tackle any opposition without too much difficulty. So far, he's taken one rank of intense training and demolition expert, lady killer, comprehension, bloody mess, better criticals, concentrated fire, all three ranks of iron fist, paralyzing palm, sniper, grim reaper's sprint, action boy, toughness, cyborg, strong back, pyromaniac, quantum chemist, robotics expert, entomolgist, life giver, and finesse. I intend to get the remaining two ranks of demolition expert, gunslinger, commando, nerves of steel, and almost perfect. I intend to max all the important skills by level 30. He's already equipped with ranger battle armor and the matching helmet, and he's carrying a powerful arsenal.
Since this character does not rely on killing from stealth, I did not invest any points into sneak, only raising the skill through the bobblehead and skill books. And the same applies for barter and speech due to low charisma.
Once this character is complete, I'll play again, this time making a stealth character taking ninja, and replacing finesse with silent running. Once done, I'll have mastered Fallout 3. Then I'll tackle New Vegas.