For soloing Hell? So you mean you want a cookie cutter guide? Are you rich? Are you poor?
A couple of suggestions.
Summoner Necro - Never played one, (Don't like Necros) but I've heard that they are good for surviving, even if they are boring. i mean, watching skellies and revives fighting is REALLY boring after a while.
Hammerdin - Massive Dmg. Takes a while to get used to aiming hammers though, and being rich DEFINETELY helps.
If you don't know what skills to put where, check out the guide sticky posts in each class-specific forum or you can visit the Strategy Compendium, but it doesn't have all the guides.
As to the above statement, I disagree. Some builds ARE better than others for soloing hell and mfing or whatnot. BIG dif between a windy druid and a suicide pally or something.
However, all characters have basically different styles. Find a character build that you will LIKE to play, and if that build can solo hell, great.