Should i do shivering isles or finish the MQ.. I never beat the MQ and only got to the quest for Bruma's allies.. And Shivering isles.. Never played it. Right now im taking Martin to the Cloud Ruler Temple.. So should i fonish the MQ or play SI.

Are you going to do both? Shivering isles has the far more interesting quests imo, although the final parts of the ob main quest is pretty epic. Personally i'd finish the main quest then go visit a certain mysterious island by bravil.

Yes im doing both.. I was thinking of finishing the MQ.. But then again wanted to have uber gear for my knight Templar in the final battle.. I think i will finish the MQ.

You're towards the end of it at least, From a story perspective you really should do the main quest first, you'll see what i mean when you get into the isles. Good luck and have fun!