My character is lvl 43, he hasnt done any main quest (only like an hour) hes barely joined the college. He will join the dawnguard (probably before main quest is finished) Ive done some deadric quests however. I wanted to wait till i get Chillrend at its strongest point (level 46) then start doing the big stuff at "max" level. Being a Frost artificer as it is, game is hard, but its fun this way. It seems silly that the savior of skyrim should have to work at joining factions, so it makes sense to do main quest last.
This is kinda bragging, but i wanted to see if anyone else feels the same way, or is playing the same way and enjoying it.