So I made a wood elf and I'm going the assassin way. Archery/One-hand/Sneak(and pickpocket I guess) etc.. I will choose between Alchemy, Enchanting and Smithing later..

Which should I choose? Thieves or Brotherhood?

Should I put some points into Magicka for any reason or keep i at 100 and keep going Health and Stamina?

I know you need one-hand for the dagger damage, so what perks do I only need in the One-Hand tree?

bump

Is there a reason why you do not want to do both?

This. There's absolutely no reason not to do both.

You can do that? Damn well thats good to know... I would have missed out hardcoe.