One of the odd things about Diablo 3 strategy that you really notice when you’re playing Hardcore is that the game is hardest in Hell. Not in Normal, or Nightmare, and certainly not in Inferno (though that can change if you climb up far enough in Monster Power.) I ranted about this in the last podcast (coming soon) and a related forum post and Blue reply gives me a chance to share my thoughts in a more coherent typed format. Those are below, first, check out the Bluth:
So, i’ve lost a few toons. I’ve been getting progressively higher but after losing my last toon (52), the same way I lost my 54, I decided to look to the forum for assistance.
Last two toons I lost were in act one, hell against an elite pack of mobs (waller, arcane). The worst part was getting walled in and then watching my health run out like someone pulled the plug on my health meter as the arcane beams annihilated me.
So the question I have is this: Is there a website(or general suggestion that can be given here) out there that lays out ideal ranges for players (level, health, dps) to achieve before moving forward in the game?
There is some great advice in this thread. Personally, I’m a big fan of life regeneration. It’s more useful for some classes than others, but Life on Hit requires you to be hitting something to reap the benefits, and that’s not always an option.
The obvious suggestions are to use the AH to stay ahead of the curve on Vitality, to take things slowly and carefully, to always have at least one 
escape skill that’s not on cooldown when you engage a boss pack, etc. (I cannot second the Blue’s advice about regen. It certainly doesn’t hurt, but 99% of death in HC comes from sudden burst damage and regen does nothing to help you with that.) All those tips are good advice always at all times (especially for Hardcore), but I’ve noticed a special danger in the game once you’re into the 50s and in early Hell difficulty.
Normal and Nightmare are very easy, once you know what you’re doing. With even moderate AH or twinked gear you can sail through the first 50 levels on MP10 or at least MP5, with your vitality enough to keep you safe and your DPS well above the curve simply by using socketed weapons with Rubies. Even just the Flawless Square Ruby adds 25 min/max damage, and that’s a huge boost when you’re using weapons with like 50-150 DPS. (And once you’ve got some money in Hardcore you can use 60 min/max damage Star Rubies which are just absurd on Norm/NM.)
A lot of things change once you get to Hell, though. The fact that Elite Affixes spawn in triples now is a big change; that greatly increases the chances of a boss having a CC + 1 type of damage and when you occasionally roll one with 2 damages and a CC that’s really dangerous. The exp gain slows down greatly as well, which can make you impatient and take risks. The real danger in the 50s comes from gear, though.
Hell monsters are much less damaging and dangerous than Inferno ones and it’s quite easy to get well above the DPS curve in Hell, moving right into the “one shot all trash range” with some cheap 800 DPS reduced level requirement item. The problem isn’t killing, it’s dying. Unless you totally splurge on -req armor (which feels like a crazy expense for just 6 or 8 levels of use), your EHP is going to suck sub level 60. Fresh into Hell you’ve generally got almost no resistance, little to no Life Steal/LoH, very little crit or crit chance or IAS, you don’t have your highest level skills for survival or to click big procs, you’re not using a shield since you never needed one in NM, etc.
All of this is true in softcore as well, but since you can get great DPS with that -req weapon (even though your FS Ruby goes from “game changer” to “is it in yet?” the minute you equip an Inferno quality weapon), Hell continues as a rush to level ups and fun killing speed in softcore. I remember doing my Monk and WD (my last 2 classes to 60) last year and blasting through Hell very quickly on a high MP level, and having fun getting them both to Paragon 6 or 8 even before I reached Inferno. Did they die repeatedly during the Hell level process? Probably. I don’t really remember, but that’s the whole point!
You can kill just that well in Hardcore Hell, but with pre-60 gear basically every class is a glass cannon in that level range, and Hardcore glass cannons create nothing but sad stories. Some weeks ago when I was leveling my 2nd HC Monk I had 2 very scary close calls in Act One Hell at around level 52, and basically chickened out at that point and got some power leveling from friends to get me to 60. That char is now P55 and I’ve never had anything in Inferno, including doing solo Ubers on MP5, that felt as close to death (and helpless in its icy grip) as I was in Hell. Admittedly, much of that is thanks to NDE (db)coming in at 58.
The knowledge of that, the fact that the game doesn’t truly start until level 60, adds weight to the pain of a death in the 50s, since you know how close you were to the finish line (which is where the race really begins in Diablo 3). I hate to recommend cheesing your way from 50 to 60 by running behind a friend and soaking up the shared exp (I might as well recommend playing a WW Barb), but it’s such a bummer to die in the 50s (I’ve lost 2 DHs there) that it might be worth compromising your principles and holding your nose at the stink of cheese for 6 or 8 levels.
