Diablo 2

what would be the best character class to solo all of hell?

I've had fun with the bowazon (bow-based Amazon) and the ice-mage. Fire-based mages have trouble in that area.

hammerdin - the noise of blessid hammer gets annoying quick

skeleton necro lvl 20 summon skele/mastery and then like level 10 revive. I had one of them once and it's only flaw was I didn't invest enough points into the fire golem and/or I didn't have a strong enough bone spirit. you either have to have a good bone spirit or a good fire golem you can't balance both and be successful - I don't like the necro animation.

another necro trick is to max out blood golem and iron maiden and makes you invincible because damage returned is converted into life... at least I think so

The game is way too easy as any character.

Your very vague here, but I'm assuming you never did Hell difficulty post 1.10 patch? By then you should be somewhere around high 50's low 60's. NPC. I had to grind to 70(Act V NM) to get a half way decent chance to consistently hit carvers. Made it to Act 2 in hell as assassin, but I could easily die with 5 hits or less, or get one hit without even a seconds' reaction time from those lightning beetles.

No, Stamina. No class should ever put any points into energy in my opinion, it's so easy to get mana from items, potions, and there the rings that restore mana when you kill something. If all else fails, hit the aura that restores hp/mana from dead bodies briefly.