So do you play the faction questlines in one big chunk or do you break them down and do a few quests then move on and then come back and do a few more?

I usually do one big faction quest (non-radiant) and then do a couple of non-guild quests.

I break it up unless it gives that feeling of urgency, such as if after one quest the evil guy is burning a town or something along thoe lines.

I have to break them up to make it seem like they're not over in five minutes.

it would be awsome that before a main mission you gotta do like 5 odd jobs and wait a week to get the next one...would make it seem that it wont take you only 2 days to become the harbringer of the companions

This. I don't like going from new member to guild leader in less than a week, so I stagger the guild quests with main quest tasks as well as miscellaneous quests.