Collection quests are hit and miss. Having gone from 1 to 70 three times (and 1 to 55 two more times), I know "bad" collection quests from "good" ones. There were collection quests that were a pain even when solo.

A bad collection quest would be the one in Hillsbrad where you collect lion blood. It's a rarer drop, and the lions are spread out. Even when soloing, this one is a pain, but it's tolerable because you run back and forth to the farm, and you can kill lions each way. I definitely skipped this one on my group.

A good collection quest would be similar to the "human skulls" one also in Hillsbrad. The drop rate is pretty high, and you can mass kill tons of humans. I did these on my group and it was definately worth it.

There are also quests that require a single item (e.g. cat's eye quest in barrens). When the single item drops, everyone can loot it. Those are worth doing.

Pay attention to the "This item begins a quest" drops. When these drop, everyone can loot it. I originally thought it wasn't worth doing because I'd have to search for these drops five times.