Most often when I played the game I play a sort of sniper character so these are some of the perks I choosed:
Awareness; gives so much infomation it can't be excluded. Knowing wich opponent has the laser rifle and the BB gun makes a huge difference in taking out the right one (okay - exagerating - but you get my point)
Better Criticals; This baby has made me one shot several opponents in the end game with the pulse rifle. Just aim for the eyes and watch them whither away.
Bonus Rate of Fire; combined with the right weapons this either let you make 3 amined shots or 2 amied shots with 2 left over MPs (at agility 10) Huge difference when taking down hard foes.
Sharpshooter; increase perception with 2 - speaks for itself for a sniper char.
Sniper; well - if you gonna use weapons - use this Perk.
With a succesfull luck roll - your shot will be a critical. Wich means at 6 luck - you have 60% chance of a critical. (and later in the game - my luck is usually 7-8
)
Tag; this one makes me take that presious high-tec weapon skill and thus increasing it twice as fast as normal. (effectively giving you 4 tag skills)
These PERKS lead up to the "ultimate" Fallout Sniper (my fav. type of combat) character
Besides this there are several others I have taken at some point or another - Gain increase in one of your SPECIAL(str, pec, end, cha, agi, luck) stats., Emphaty is nice etc.