Weapons by use:
Caster dagger - Valiona
Caster dagger - Magmaw
Caster sword - Conclave of Wind
Caster mace - Cho'gall
Caster mace - Nef
Rogue dagger - Omnotron
Rogue sword - Valiona
Rogue dagger - Cho'gall
Rogue axe - Nef
Tanking 1-sword - Maloriak
Melee 1-sword - Conclave of Wind
Melee 1-sword - Magmaw
Melee 2-axe - Cho'gall
Melee 2-mace - Magmaw
Melee 2-sword - Nef
Feral staff - Halfus
Bow - Atramedes
Bow - Valiona
Trinkets:
Caster - Valiona
Caster - Atramedes
Caster - Cho'gall
Caster - Council
Healer - Maloriak
Melee - Chimaeron
Melee - Council
Hunter - Halfus
Hunter - Nef
Tanking - Magmaw
Tanking - Valiona
We can also look at the success or lack thereof from other guilds. I went to Guildox today and pulled out kill stats and average ilvl information for each boss. (Average ilvl is based on both 10 and 25 kills, so not the most useful information.)
Boss | 10-man Guild Kills | 25-man Guild Kills | Average ilvl |
Halfus | 2796 | 1636 | 352.5 |
Chimaeron | 1364 | 1104 | 352.7 |
Maloriak | 643 | 623 | 354.1 |
Atramedes | 522 | 483 | 354.0 |
Conclave of Wind | 189 | 429 | 354.5 |
Omnotron | 133 | 266 | 355.5 |
Al'Akir | 86 | 15 | 358.8 |
Magmaw | 69 | 345 | 355.3 |
Ascendant Council | 5 | 56 | 357.8 |
Nefarian | 3 | 44 | 359.1 |
Valiona | 1 | 121 | 358.1 |
Sinestra | 0 | 26 | 358.0 |
Cho'gall | 0 | 43 | 359.8 |
I guess the Sinestra number shouldn't be a surprise since no one has even killed Cho'gall yet. The boss with all the drops I want (weapon, trinket, and tier piece from one boss!) has only been killed by 69 10-man guilds which is a shame, though the average ilvl is much lower than the end bosses so he may be doable. It certainly seems like Chimaeron is the second most popular heroic to kill though he drops practically nothing in super demand by my arbitrary criteria.