Aye, I don't really trust 3rd-party publishers to make balanced spells and magic items, at least not a majority of the time. I've seen some pretty crazy-powerful things done in 20th-level games by folks using a bunch of 3rd-party books of spells and magic items to make their characters invincible, for all practical intents and purposes (it would have taken direct combat with a deity or extremely-terribly-epic-level character just to stand the slightest chance of not getting 'owned' by those characters). Consequently, I don't game with those people anymore.
I haven't had any problems with dragons so far in my games..... They definitely have somewhat lower AC and attack bonuses than PCs of similar CR, but not too much worse, and they can be pretty effective if run properly (they have years to plan, and centuries or millenia to live! their concept of hasty thinking is generally similar to a human's longest-considered-and-most-thought-out plans! as others mentioned, retreat or repositioning for them is like a minor tactical adjustment. also, they have every reason to possess well-guarded lairs, with highly loyal minions and advanced traps).
They don't need to have plans based on metagaming, but just mere knowledge and experience. Dragons who survive to adulthood generally have decades, if not centuries, more experience in the world and its dangers than most adventurers ever accumulate, except possibly for veteran elves and dwarves and such. Some dragons are likely taught lessons by their parents, and dragons are born with intellect and sensibilities similar to a human adult's, so they learn fast. A dragon will gauge his or her foe in a brief skirmish or flyby, or through minions, and try to ascertain what kind of foe he or she is about to face; they will likely know some of the key signs of what foes are likely wizards, what ones are likely clerics, what ones are likely barbarians, what ones are likely rogues, and so on; by noting certain types of gear or action by the observed foes, the dragon will likely be able to guesstimate what exact kind of threat he or she should expect out of them later.
The dragon will likely try to wear them down or dishearten them before any direct confrontation; a brief fly-by breath weapon attack maybe, or a few of those, or a small force of minions sent out to harass the adventurers and one to follow those minions secretly and report back on what exactly happened and what the adventurers looked like. An evil dragon might attack a nearby town first, and goad or tempt the adventurers to go and help the town as it burns and draconic minions run amok; then the dragon will either attack briefly while they're distracted, or wait and see how many of their resources they spend in the effort, then determine the best time to attack. The dragon will make use of its superior natural senses and other abilities; it could even terrorize animals into a stampede that reaches the adventurers, and harms them or expends some of their magic in ending or surviving the stampede.
They will use terrain, weather, and other features to their advantage. They will know their hunting grounds like a human knows his own house. They're bigger and they live on a bigger scale; to a dragon, memorizing the landscape of a valley is like memorizing the layout of a house and yard, while memorizing the pitfalls and quirks and general denizens of a cave complex (or small forest, etc.) is like learning the nooks and crannies of a kitchen.
Dragons not only have much higher average mental ability scores than the PC races, they also live much longer and experience a lot more even before adulthood, so they have more time to develop their wits and lore into a series of elaborate and cunning plans, for use in the inevitable fights to come. They may not know the PCs from any other Puny Joe Human, but unless they're still in their first 2 age categories or thereabouts, they probably know the signs of what kinds of Puny Joe Humans the PCs are, by the looks and sounds of them. The dragon may have enough Spellcraft to notice what the PCs are casting when they fight his minions earlier, too. The dragon can likely guesstimate the general competency/power of the PCs based on their activities within his/her hunting grounds, as described by his/her minion spies/scouts or as seen in his/her own flybys (flybies?).
Kind of interesting and scary sidenote though: with the 3.0 core rules and the Psionics Handbook, a halfling psion can have AC 62 (69 in melee with against a single foe, 67 at the same time against multiple foes) at 17th-level onward, and that's not even considering the use of Polymorph Self, Metamorphosis, or similar powers, nor any artifacts of course. They'd be almost impossible for anything but the biggest-HD monsters to hit, though they'd have relatively mediocre or weak offense, and no real utility items (though a few utility powers). If not for the GP needed to properly own the magic and psionic items for that AC, the halfling psion could just as easily have that AC at 12th-level instead. AC 40-something would be easily doable at almost no GP expense for this psion at 12th-level (just buying ordinary or +1/+2 full plate and large shield, and maybe a +1 defending weapon and a +1 ring of protection; haste and barkskin potions could also be used instead or in addition).
Example: halfling seer psion 17; strength 14 (boosted to 19 with Maximized Animal Empathy; probably started as Str12 before natural increases applied at 4th and 8th level), dexterity 13 (boosted to 18 with Maximized Animal Empathy), constitution 14 (again, boosted with Maximized Animal Empathy, to 19), intelligence 13, wisdom 20 (base of 18 before increases at 12th and 16th level), charisma 8; feats would include Dodge, Psionic Dodge, Expertise, Maximize Power, and anything else they feel like; psionic items would include a Psychoactive Skin of the Hero and +5 Mithral Full Plate Armor, while magic items would include a +5 Animated Large Steel Shield, a +5 Defending Light Mace, a +5 Ring of Protection, one or more Potions of Haste, and one or more 12th-caster-level Potions of Barkskin; relevant psionic powers would include Animal Affinity and Shield of Prudence, but also helpful for non-AC defenses would be the powers Inertial Barrier, Displacement, Amplified Invisibility, Precognition, True Seeing, Fate Of One, Dimension Slide, Improved Biofeedback, Ubiquitous Vision, and Steadfast Gaze, and the character's offense would consist of such powers as Greater Concussion, Mass Concussion, Dissolving Touch, Recall Agony, Whitefire, Burning Ray, and Cone of Sound, also likely Emulate Power and Recall Death; the AC calculation would be 10 base, +1 size, +3 Dex (limited by the full plate), +13 armor, +7 shield, +5 dodge from the Defending mace, +5 deflection from the Ring, +4 haste from the Haste Potion, +3 luck from the Skin, +5 natural armor from the Barkskin Potion, +6 insight from Shield of Prudence, and in some conditions +2 to +7 dodge from feats; AC 62 to 69. The power Natural Armor could be substituted for Potions of Barkskin, but the AC bonus would be 1 lower. If the power Psychofeedback were used, and armor were abandoned, the AC could go higher from Dex-modifier-boosting but only for a few rounds, and at the expense of massive amounts of power points. If Oriental Adventures or other official 3E D&D books were added to the mix, there'd be even more AC boosting available, such as the Superior Expertise feat from OA.
![:]](http://www.enworld.org/forum/images/smilies/devious.png "Devious :]")
*LOL* 
