Tale of X Gamers - The Heresy Edition

Over at Fields of Blood Pete has put out the idea of a tale of 'X' gamers based on the new Horus Heresy books from Forgeworld.

I was already interested in starting a 'Legion' army so this sounded like a perfect excuse. 

I've decided I want to do a loyalist legion, based near the beginning/before the Heresy really kicked off. The armour of choice will be MKIV Maximus type and Tigrus pattern Bolters as these are my favourite designs. I may slip in some MKV Heresy armour for good measure, and at least one squad will carry Umbra Ferrox X10 Bolters. I will build it around one company within one legion chapter so I can build a story around them and make up some characters.

My main problem is what Legion to make. Having already decided to go the loyalist route, I can already discount Blood Angels, Space Wolves, and Ultramarines. We see enough of these already. 

So that leaves me with Imperial Fists, Salamanders, Raven Guard, Iron Hands, Dark Angels, and White Scars. Unfortunately the best resource for these options will be in the books yet to be released...

Any suggestions?