Molten Core late last night. With the release of WoW, Molten Core was the only 40 man instance. I needed to kill Ragnaros for the Molten Core Achievement, but the only way to summon him was to defeat the other 9 bosses! With the upcoming release of Cataclysm, Ragnaros will return located in Sulfuron Keep within the Firelands.
While technically there are no prerequisites to enter Molten Core through its entrance at the bottom of Blackrock Depths, every raider will want to complete the Attunement to the Core quest to enable the shortcut at the bottom of Blackrock Mountain. This quest is given at level 55 by Lothos Riftwaker who is located just outside The Quarry on the way to Blackrock Depths. Once attuned you can access Molten Core by talking to Lothos again. We ended up jumping into the Lava near Lord Incendius and swam north to a ramp that took us right to Lothos.
Once we had our Warlock attuned we then summoned the rest of the raiders into Molten Core to begin. Our group was a mixture of levels from 54 to 80. We had one tank, a Warrior who actually was quite good and one level 80 Druid Healer. I could see a group of five geared 80's having no problem with clearing this instance. We had 12 total toons with more then half 70 or lower and one of them was my Shaman, Tyru; who I had following me so he could get the Molten Core Achievement as well.
One of the best things about Molten Core was the reputation given with the Hydraxian Waterlords. I always wondered how to grind that rep and now I know. I went from 0/3000 neutral to 1034/6000 friendly. We probably skipped some trash on the way, but it would probably take 10-11 runs to become Exalted with them.
I can't really give you any tips on boss strategies because we just burned everything down within a few seconds. Just remember to defeat all the bosses on the way to Ragnaros because you don't want to get all the way to the end and realize you have to go back and find a boss you missed. The instance is a lot of fun and I recommend everyone try it at least once. I'm going try and join groups for it whenever they are forming so I can one day be Exalted with the Hydraxian Waterlords!
The completion of Molten Core left me with three more Classic Raids to finish the Classic Raider Achievement.