The backbone of any Knight army are the Paladins and Errants.
The Paladins are the guys with the Chain Sword, the guys with the gauntlet are Errants.
Designwise they remind you to the newer GW models. They are quite different from the old Epic models.
When I started I had some ornaments on the legs and shoulder, but removed them to give a cleaner look.
If you're a damsel in distress, you will - obviously - call a knight.
Let's say, you ran out of that (you know which one) red nail varnish and the Imperial Soiree will start in just twelve hours - a Knight Errant would be a sensible choice, with the big hand of his, he's just perfect for fetch and carry type errants - guess where he got his name from.
Let's say, you're not sure whether that red nail varnish, will be appropriate for the occasion, you'll call a Paladin, well versed in anything related to the Emperor, guess where he got his name from.
But let's say you have some distress caused by a monster in your closet or a chaos spawn rampaging through your dungeon or a mother-in-law trying to settle in, who do ya gonna call ?
They are even cleaner and smoother than Paladin and Errant, the body armour encloses the torso, there is also some additional protection to the upper leg. The helmets are grimmer and the models are 10% larger than the other knights.
The Wardens are basically Heavies with lighter armament. I thought about giving them their own design, but couldn't find any excuse for doing so. They just seem to be Heavies with lighter weapons.
These are all from the Flak variant, it's the only one I find really useful. Might be that I change that opinion, once I have more practice playing Knights.
If you want a Supreme Commander, you will have to pay through the nose - 200 Pts for a Baron. Whether he is worth it is for you to decide. I did a model anyway. I based him on the Heavies, because that guy can afford the best money can buy.