As an alliance player I followed the Jamie's Alliance Levelling guide on wow-pro.com. (though I know most of the quests already, I just used it as a reference on where I should go if I was running out of quests...)

Everytime I hit a collection quest (especially in Outlands) I would look it up on wowhead.com and decide wether I would do it or not based on the following criteria :
- Amount of follow ups and wether they involve more collection quests or not
- The reward of the specific quest or the follow ups
- The amount of mobs and wether they are spaced out or not
- Skim through the comments to get an idea of the droprate

Obviously if a collection quest has a good droprate with alot of mobs, has alot of easy kill x mobs followups with an elite at the end of the chain which gives you a great new item, I would do the quest. If not, just skip it and move on.

Worked fine in combination with the Jamie Alliance Levelling guide. I ended up doing some collection quests, though skipping most of them.