first:: Who would use armageddon on a ranged pack? thats what the other 4 fire skills are for.
Second:: arctic blast isn't always the best skill to use, I just mentioned it mostly for use on hell cows, although there are other areas it has uses for. Twister is also good for spamming, stunning even lister and the others.
as far as hell cows go, if you have max block (and you should, for sure), then they aren't that dangerous, and the appropriate spam will keep them off your back for sure. also note that I said armageddon wasn't the safest and that fissure was.
My grizzly bear is maxed (note that I don't use armageddon on the fire elemental in question), has about 5k life, and dies in seconds in hell in darned near any situation, but especially vs. diablo. this is why I said fissure was best to use here. With max block and resists (and sometimes dr), tanking act bosses is a pretty decent idea, imo. firestorm tears them up (note that I couldn't get baal to stand still until I was *right* next to him, so 7/8 of volcanos damage was piddly fireworks). If you are right next to them, often they won't use their ranged attacks and will try to melee you. Also true of duriel. His charge/running attack is annoying and deadly, but if you get a lot closer, ie. firestorm range, he tries to normal attack you or smite, not such a deadly attack although you will use a few reds sometimes. Just keep "spamming" and you will do fine.
anyways, for a pvm build, I never once recommended using armageddon, just that it was indeed viable. I also said that you need to know which attack to use where, and that my opening statement was you need to use strategy.
to the original poster:: Its NOT an item dependant build, but there are a few things I would make sure you do.
you dont' really need fcr, but some sure helps.
Get max block. geddon or not, you will need it.
Get max resists, same rule applies.
Keep your strength low and what you can, put into vit.
lower level runewords rock for this guy. Lore, stealth, and rhyme are all viable end game options, but try to get resists/skills where you can. a great idea would be to go ladder. A spirit sword rules, all the way thru hell. There were times when I needed the wizardspike I found, though. don't try to get a whole lot of magic find for this guy, but there are great places to mf with him that other builds aren't so great for. Late act 5 (tunnels, etc. are GREAT), act 1 mausoleum/blood raven are great for exp and NO fire immunes. Blood raven has duriels level (**..higher than mephisto, even), and always seems to drop rares/a fair amount of runes. Countess is also good. while she is always fire immune, a cano up her rump is a great way of getting items and fissure tears up her minions. Note that i made it all the way thru hell solo with my fire ele, but I made some great finds along the way (tgods, ss, wizard spike). I had max block, a maxed grizzly, the first 4 fire skills, and a rogue merc with cold arrow. Harmony rules for this girl, so don't rule that option out. If you can, get a wand with lower resist charges. It really ups your damage in dangerous areas (gloams, etc.) and can speed up magic finding, if thats what you want to do. Have fun!
--welt