Crystals section? Some that catch my eye are
Demolition Crystal, Greater:(MIC, 1,000, 3,000, 7,000) Sneak Attack Constructs, one of the of the weaknesses of the rogue. Also +1d6 on constructs and adamantine properties. Not bad.
Crystal of Return, Least:(MIC, 300, 1,000, 4,000) Draw as a free action, and the greater version gives it the returning property. Easily full attack with many magic thrown weapons for much cheaper than you'd pay for enough to throw each one once.
Crystal of Arcane Steel:(MIC) for 6,000 gp a duskblade can buy weapon focus, a wimpy-er version of weapon specialization, and Spell Focus (anything) when delivering their signature touch spells. Not at all bad, I might say, but sort of limiting. Although they are insight bonuses, so they'd stack if you really wanted to stack them.
Crystal of Arrow Deflection: (MIC, 5,000) Only the expensive version's worth it, but you get a feat AND a +5 AC on ranged attacks. Near invulnerability against the weak point of many, many, many builds? 5,000? YEAH! Applies to ranged touch attacks and can probably deflect things like splinterbolt and icelance as well, maybe even meteor swarms.
