I've only recently discovered the sheer joy of the barbarian. The hit dice, speed bonus, BAB, and decent skills are a wonderful package. Raging is just a fun cherry on top for that fight where you really need to do boatloads of damage.
-blarg
Cool stuff nearly all the way over 20 levels. Max skills. Brutal conditional (tactical) damage-dealing capability. Achille's heel (yes, I like the fact they can't SA certain things; bite me). They're just awesome.
Yes, I often dip Barbarian with Rogue, too. At first, it was merely because I thought the ability to search for traps and not slow the party down (moving at speed 20) would be important. But, yeah. The infusion of the d12 and at least +2 fort really helps cover Rogue weak points, Rage can help make you useful against enemies you can't SA, and the weapon proficiencies are just icing.
Aside from the dips, I've also found the joy of a 2:1 or 1:1 Rogue:Barbarian multiclass leveling ratio if you have things like Martial Rogue (UA) and Lion Totem Barbarian (C.Champion) available. Learn enough "trick" feats and you can fight like a martial adept!