Jerry Teo of Mystic precision made a post back in like 2007 that is what I went off (and still do) when buying dies. Basically, the BIG thing is to never use full length resizing dies as it is bad for both brass life (excessive work hardening of the brass) as well as concentricity.
To achieve the best concentricity as well as reducing the damage you're doing to your brass at the reloading bench, use a dedicated neck sizer (I use the Lee neck only die as they are way cheaper than the Redding ones suggested above and IMO, do as good of a job, but he raises a fair point about work hardening and neck tension). Buy a dedicated body sizing die (Redding is my pick, and the only one that comes to my mind). Use that body sizer ONLY when you notice it's hard to close the bolt on a fresh round, for my 223 this is usually once ever 4 loadings.
Bullet seater dies are easy; I use the Forster ones myself; I like the box they come in, nice and big and closes over my Hornady quick change bushings. I have both a micrometer seating die for 308 and a non-micrometer seating die for 223. The micrometer is nice, but not really that important.