There is much talk along the lines of "Codex 'A' has character 'B' in it and therefore MUST be used to represent chapter 'C' or the world will end". This is blatantly bollocks and so I'm going to list which books (imo) can be used to represent the different armies and give some reasons why and perhaps list a few alternatives that may not have occurred to people.
In the interests of keeping some semblance of order I'll do them in order of founding,
No. 1 - Dark Angels.
Obviously the Dark Angels have their own codex so it would seem to be the obvious choice. If your doing a 'Deathwing' or 'Ravenwing' army then it probably is (especially after the recent FAQ).....However.....
Dark Angel players not doing either of the above mentioned themes are somewhat stuck with an outdated rule-set. It's obvious to most people that the Dark Angels Codex was a 'test-bed' for rules that would inevitably make their way into the Space Marine Codex, therefore I see no reason why the standard Marine codex can't be used to represent them. Given their background as a knightly order using the Black Templars book is also not unreasonable ;-)
No.2 - ???.
No.3 - Emperors Children.
The Chaos Codex has Noise Marines in it and therefore has to be used to represent them.....Of course that's only true if you believe all Emperors Children became Noise Marines which they blatantly didn't and that having an extra point of Initiative represents worshipping excess in all its forms which it obviously doesn't.
Pre-Heresy Emperors Children (being just like normal Marines) can be represented using any book you like. Post Heresy is a bit more tricky.....Though it seems like I dismissed it as a choice the Chaos Codex can be used to create a fairly 'fluffy' pure Slaanesh force which is still usable (though not optimal) as Noise Marines only really become Noise Marines once you give them a Sonic Blaster.....
Also though Lucius the Eternal is available as a character in C:CSM he can be represented in real terms by anybody who's good with a sword and there's no shortage of those in the other Marine codices. As the EC were a chapter obsessed with perfection but with an extremely well defined command structure, the Blood Angels codex could represent them just fine as 'Feel no Pain' is entirely reasonable for Marines who actually quite enjoy pain and 'Furious Charge' and 'Red Thirst' just represent the uncontrollable craving for more of the sensations of battle.....Well it's just an idea, lol.
No.4 - Iron Warriors.
Lets cut straight to the 'Obliterator' argument and get it over with. Yes, the Chaos Codex has Obliterators in it and yes the Iron Warriors are associated with them but they're meant to be exceedingly rare so therefore 9 of them turning up to a 1500 point border skirmish isn't Fluffy.....
No, it isn't......
For a bunch of siege warfare specialists the 'Vanilla' Space Marine codex is a better fit. Masters of the Forge, Ironclad Dreadnoughts, Thunderhammer/Storm Shield Terminators, Vindicators with Siege Shields and Thunderfire Cannons could all be included in an Iron Warriors army without any stretch of the imagination being required.
No. 5 - White Scars.
Well this is one of the few ones where the intended codex fits them perfectly. Bikes as Troops and a special character that gives you 'Outflank' is ideal. Though remember that just because you can outflank with everything doesn't mean you should outflank with everything.
No.6 - Space Wolves.
They have their own codex and it does the job just fine.
No.7 - Imperial Fists
I could just copy/paste the Iron Warriors entry above into this section, lol. The reason the Iron warriors fit so neatly into the Space Marine codex is exactly because there's plenty of Imperial Fist suitable units. Lysander doesn't have to be in an Imperial Fist army by the way.....It's not compulsory or anything.....
I think that'll do for now and I'll start the next article with the 8th Legion - The Night Lords
Thoughts and comments are (as usual) most welcome.
You have read this article Thinking out loud with the title Representing the Legions - Part One. You can bookmark this page URL http://llourenzzo-putta.blogspot.com/2011/03/representing-legions-part-one.html. Thanks!