With the defeat of Faction Champions and the Twin Valkyr in Trial of the Grand Crusader, we are currently (Feb 24, 9:09 am PST) #12 on Drenden 10 Man Strict Rankings. Our next achievement will take us up to 8th (Now 5th), and the next after that to 6th. From that point, each achievement will move us up one rank per until we hit #3 (Now #1). The #1 and #2 spots are taken up by guilds that were clearing 25 man ToC before Icecrown. They're not really 10 man guilds, but are instead inactive ones that have a lot of 10 man achievements but no modern 25 man ones. We're 5 achievements from the "top" (Now it's the real top!)! To see the list of achievements that are taken into account, go here. There a lot of achievements that we could certainly do, including:

The Spellweaver's Downfall
Twilight Duo
The Twilight Zone
The Antechamber of Ulduar
Call of the Grand Crusade (10)
A Tribute to Skill (10).

*Update - The #1 and #2 spots have been freed up. We can take #1 if we get on it. It would mean delaying progression, but it might be a good idea to open each Tuesday with the accomplishment of an older raiding achievement.