So I posted a similar conversation starter over to the Eldar board.
I am wondering about how people came about to a preferred army style. Did the fluff come first, or did the list come first? What were the influences, so on so forth.
With my guard, I started it knowing little of the 40k fluff to be honest. I mean I knew it superficially, anyone who hovers at the edge of table top gaming, such as pin and paper RPGs, strategy PC war games, etc... picks up a little of the fluff. I picked Imperial Guard because they seemed, to me, to be pretty bad ass. When I was building my army, I didn't really have much of an idea of my fluff. I wanted tanks, so most of my buys were tanks. I was also reading the Guant's Ghost books to get a better idea of 40k guard related fluff.
After a few months, my army fluff took shape. The Rivirsigh regiments were all, to the last member, all volunteer forces. Rivirsigh had, as law, that to be a formal citizen and gain the right to vote, equal protection under the law, you had to serve in the government service, with PDF and Guard being the most plentiful service to join. Rivirsigh itself is a fairly normal world in terms of Geography, and while it has a few hive cities, the majority of cities are small to medium, and most of the exports are agricultural in nature. The 32nd, the regiment I field, comes from a Mediterranean/desert area, and has a reputation of producing officers and soldiers who perform well in desert environments, gaining the regiment the nick name "The Desert Rats."
The style of the army has always been aggressive foot soldiers supporting an armored advance. Russes, the hell puppy tanks, with sentinels and some Chimeras in support. They advance up the field, using tanks to provide cover for infantry as they advance over the empty spaces, and infantry providing small arm fire support to allow the tanks to focus on large targets. The fluff has taken the driver seat for my army, by and large, with the aggressive blitzkrieg style assault.