I'll have to see if I can get TOH2 and CC3, as I have the "prequels" for these and reasonably enjoyed them. I would also add and amen for Frost & Fur, but it falls down a bit in both the art and the game mechanics (particularly on the prestige classes). Based on eveything else, though, I rate it vastly superior to Frostburn (and I like Frostburn).
I will now perform a mini-thread hijack and pimp my favorite D&D book even though the art is not WOTC-quality (and WOTC often bugs me with over-spikey armor and caricatured orcs). Green Ronin's Complete Shaman's Handbook is by far the best 3rd ed D&D supplement I have used. The shaman as they present it is much better for a generic animist caster than the core druid, and most of the prestige classes are quite good (and many are for non-shamans). One can buy the book and start using the shaman class for most tribal and humanoid spellcasters without breaking a sweat or making major (or even many minor) changes to the campaign world. It has totally driven the adept class from all my game worlds. OTOH, the art is fine but not great. It is technically a 3.0 book, but 3.5 update on Green Ronin's website can be summarized as: change on the skill names that changed (e.g. wilderness lore), and fold into class skills the skills that changed into classskills (e.g. scry). In general I find more use for Green Ronin supplements than TSR ones, but this one should seriously be on every DMs shelf.