Nim,
To expand a bit on Hunters. They are probably the ones who can accomplish most special tasks.
1. Hunters do pulls. Sometimes, not merely because it's handy, but because they are the only ones able to safely split an NPC/group from the rest, due to range and FD. A clear example is the Kurinnaxx encounter (Ruins of Ahn'Qiraj).
2. Hunters taunt through Distracting Shot. Either to allow the tank some respite, or to control adds. Another clear example would be Hakkar's wind serpents.
3. Hunters are the only class in the game who can CC long-term 3 NPCs at the same time. 2 through Freezing Trap (by placing the 2nd Trap after the first is activated) and 1 through Wyvern Sting. Sadly, this was a lot more useful in early TBC Heroics than during Classic, which was a lot more forgiving.
4. Hunters kite. Lots of times. Lots of places. Sometimes, you would kite an add to the beginning of the instance to allow your raid to finish the rest. A good example would be the Anubisaths in Ahn'Qiraj. Ossirian too. Your first relevant kite will be in UBRS, where you kite Drakkisath until the party/raid finishes the adds.
5. Hunters dispell Enrage/Frenzy through Tranquilizing Shot. On Magmadar, Chromaggus, Kurinnaxx again, Gluth etc.
6. They also have a good range interrupt in Scatter Shot.
7. Finally, as a perk, Hunters are able to survive a wipe through FD, enabling them to then resurrect a healer with Jumper Cables. If you're deep in Ahn'Qiraj, you'll really appreciate this.
EDIT
8. Hunters are also employed to Viper Sting during certain encounters, such as Moam in the Ruins of Ahn'Qiraj.