It depends on the character, doesn't it?

Super Slam is phenomenal for melee/unarmed characters - it's particularly helpful against really tough foes.
Robotics Expert was my favorite perk in Fallout 3, I haven't tried it in FONV yet but I imagine it's still quite useful.
http://www.gamesas.com/index.php?/topic/1137390-what-is-the-best-perk/
Yeah, let's continue this thread in there. Thanks for the link delra