i am going to start a pre heresy army. I am just having trouble pinning myself down to a legion.

I have narrowed my choices down to:

iron warriors; blood angels; thousand sons; word bearers, or Alpha legion.

And ive also been considering dark angels, imperial fists, or night lords though these arent the favourites for various reasons.

whilst it may not seem like thats much narrower (just under half the available legions), for me thats quite an achievement due to my indecisiveness.

thoughts and opinions are more than welcome...

Hmm, tough decision...

Most players go for traitors before they turned mainly because they are different to the modern day chapters.
Word Beares in their grey armour would be cool, their religious zeal would make for nice models and convertions.
Blood Angels whilst not that different to the chapter as it stands now could be fun.
Thousand Sons are extremely popular, Iron Warriors are fairly scarse as are Alpha Legion.
Depends what sort of army you''re after and what appeals to you.