When deciding section ID, one should not only think of which ID gives the best equip for the character, but also which ID the character excels at hunting at. For example while Hunters may want Sealed J-Sword, RAmars and RAmarls have the easiest time hunting it from PW4. People often end up with a character that is not so great for the task, although powerful classes can still manage.
Back on topic of which ID is best for what class, apart from what has already been said, V101, V502, Red Ring are also general best drops. V101 in particular is very important and heavily affects an ID's rating.
For Hunters, while Skyly has all the high ATP swords, the best sacrificial ones are best hunted on Yellowboze (high hit Zanba, high hit Flowen 3084, however both are very rare). Viridia's hit Yunchang is also worth a mention.
For Hunters and Forces, Redria has the best Diska of Braveman drop (but it can also be obtained from Forces' Lucky Coins), and Oran/Skyly has the best Slicer of Fanatic drop.
For Rangers, Cannon Rouge (Redria/Yellowboze) is also a good thing to get.
Alternatively you can pick the ID which synergize with your outfit.
Edit:With the change to the rate of getting hit % in Ep2 (1% -> 5% for most IDs), best DoB drop is now Whitill's Gees and Gibbons (PW2). Hit Zanba is now huntable from all IDs that drops it.