23? I'd go back to the archives and level up to 27. If you insist on pushing through as fast as you can on HC, you'll die eventually. I find cleave better than bash. Earthquake usually takes out the guards... that and a couple swipes.
I'm too bad at not dying to ever consider HC. So what gets me past bosses without dying midfight should work even better for you, right?
My DH found spamming bola shot + thunder ball highly effective against (normal) Diablo. It won't lock him down completely, but he should be attacking a lot less. I suppose other sources of rapid stun, like bash + clobber, might be good as well. But I've never tried them myself.
I've also generally found the monk to be a great survivor in normal and NM, especially due to the healing skills. Aside from the obvious ones (breath of heaven, serenity + peaceful repose), I'm also a big fan of Transcendence. It might not be spirit-efficient, but it's a heck of a lot better than dying because your big heals are on cooldown. Mantras work particularly well with it, due to their recasting bonus. I personally prefer mantra of evasion + hard target, although I've also heard good things about mantra of healing. I also used crippling wave + mangle and resolve, but I'm not sure how effective they actually were against bosses.
Cheers for the help. About to face down Zultan Kulle (awesome voice acting, btw, along with Covetous Shen) - with a Dual-wielding HC Barb at Level 27 with 4200 hp. Using Bash + Onslaught, Rend with Bloodlust, Revenge with Vengeance, Threatening Shout, Leap, Earthquake.
Not certain what Passives I should be taking to maximize survivability while still staying 2H or Dual-wielding as I knock of Normal difficulty. Currently with Nerves of Steel and Bloodthirst but internally debating Pound of Flesh and Inspiring Presence... mostly socketing for Vitality, so gaining armour should be good, I guess.
UPDATE: Shortest bossfight I ever saw. I may have taken damage but didn't notice it if I did. He did get off one slow bubble, both adds died to Earthquake quick as hell, barely got off a second Rend...
For general play it's hard to beat Cleave with Reaping Swing while leveling in Normal, with Rend + Ravage. For bosses I switch to Bash + Onslaught and Rend + Bloodlust.
My barb was dual-wield, Level 35 and with 5026hp when I took down Diablo Normal last night. With all Rare equipment from the AH, but a lot of the gear was level 23-ish. I had enough safety margin to run around a bit and really make sure I knew what was going on in the fight, even got caught by the Bone Prisons a few times with little trouble.
Going slightly off-topic, I'm totally in love with cleave + rupture. One of the most satisfying experiences in the entire game. And amazingly effective against high HP monsters surrounded by little, squishy ones. Although I can definitely see how the extra fury from reaping swing could save your butt in HC.
I'm thinking SC play is hugely different from HC here, as is the decision to go dual-wielding v. 1H + Shield.
HC SP Dual-wielding at Level 48 with 15k hp and decent Rare/Legendary-cheap gear and just finished killing Ghom I'm having to really watch what I do, using Cleave and Rend/Bloodlust, switching to Bash/Onslaught for bosses.