First Diablo 3 character
Of course we don't know what classes, skills there will be in the game, so let's just assume the same archtypes (mage, ranged shooter, summoner, melee fighter etc.) like in D2. Also let's cross the fingers that the stupid requirement to complete SC before going HC is lifted. And the only requirement to post in this thread is: you don't do any prior try outs of various builds (preferably making the decision by reading the official 2 sentences description). Of course we all can have different goals for the first character so feel free to highlight it. So basically you don't know how the game plays, but still you make HC character to find out.
If itemization stays the same (I hope so! talking about MF runs and unpredictable drops from both mobs and bosses), playing character dependant on gear without having some gear to start off is not for me. It's hard, but more in a sense that it gets boring to hit for no damage, constantly be out of mana because of no leeching, drinking healing pots during every single encounter. Don't really think it adds to the real challenge, rather those classes/builds are forced into leeching their way through until they get at least decent weapon which anyway requires upgrading often.
Also I don't want to experience insta death first hand, although I am pro-insta death. But the beauty of it is when you know something is leathal and avoiding it conciously, in other words making right decision. I'd rather learn from others mistakes. As you can see I am not really a care bear and I will probably make fun of people dying

So that suggest I should choose more of a passive build; that would let me observe the events, boss fights not staring at my health bar. But not as passive as a summoner necro. That's a bit too much passiveness for my taste. Ok I am running out of time now so I will just end for now by listing a few classes/builds which come to mind: summoner druid, bone/poison necro, amazon, high mana regen/energy shield sorcerers, trap assassin, caster druid. Will elaborate on them later.