I don't recommend Knight, if only because you have to put points in charisma, a score dwarves get a penalty to, and wouldn't have any use outside of the stupid taunt ability. Now, if you could somehow pick up some charisma to saves or something, it may be worthwhile.

Personally, I'd skip fighter and the other feat based martial classes in pre-ToB and look at a Deepstone Sentinel build. Many ToB maneuvers set DC based on str, rather than some worthless mental stat.

Fullplate is crap unless you get it made out of mithral, in which case, it's the next best thing to a mithral breastplate. Adamantine fullplate won't be useful for a dwarven defender, since damage reductions don't stack, RAW (though some of them really should). The +2 vs touch attacks from a higher dex can be really helpful, esp vs. enemies who have low BAB. For every one point of touch AC you get, a caster needs two levels to meet you with BAB.