One thing I've heard, but it seems accurate and is likely what the discription meant, is about luck. Using an item with any luck in it has a small chance to increase it's luck.
As I said it seems right, but I haven't actively tested it.
As I recall, that's the official line. Putting 1 piece of lapis on a tool will give it the chance to get Fortune/Looting to the next level, but the chance increases for each piece. Geting it to the next 150 mark it forces a "level up". Note, that the chance only applies where the enchantment would be called (i.e. if you mine coal, rather than stone).
WRT effects (which aren't very well detailed in the books), I think they work this way:
Stonebound: Mines faster/does more damage the lower the durability is. Presumably this is a sliding scale with the average being the stated mining speed.
Jagged: Inverse of stonebound. Does more damage the higher the durability.
Reinforced: Has a 1:X chance of the tool taking damage when mining (effectively increasing the durability in a linear scale).
Writable/Thaumic: Adds an additional modifier/
Others such as knockback/luck/beheading/smelting/etc. are explained.
Notes for tools:
As far as I know, mining level/speed is affected by the head (and plates), and durability modified by the handle. The binding does not seem to impact either, meaning that you can get additional effect by choosing your binding carefully.
Materials of significance:
Early metals: Basically down to what you have, and what it gives. Go with what you are plentiful in.
Steel: The only non-TC alloy capable of mining cobalt and ardite.
Slime (green): Best handle modifier pre-manylyyn.
Notes on modifiers:
Diamonds/Emeralds: Diamonds add 500 durability, and emeralds double durability (can both be used). So, use diamonds when your durability is less than 1000, and emeralds after. Diamonds also allow you to mine obsidian.
Charging: If you have the infrastructure for EU, this is a very good way to do away with the need for durability modifiers, leaving you with more space for other things. This also means that durability in the tool makeup is meaningless, meaning that you can select the head for speed and make the rest out of paper for the modifiers.
Fortune/Smelting: I believe that (when interaction is turned on, as it is in the last few versions of the packs) this has the ability to beat out even the factorisation processing lines. Note, applies to anything that will drop items when cooked (logs, potatoes, ores, etc.).
General notes on the mod:
There aren't enough modifiers to have a one-tool-for-everything tool. But, when you get to the nether-material stage, it is worth adding something to prevent yourself from needing to repair them, either charging or auto-repair works well, if you can support it charging is best.
For diggers, the only really key modifiers are: Luck, smelting, silk-touch and speed. I'll usually load up on luck (and possibly smelting), charging and then a huge amount of speed.
For weapons, it's more complicated. Beheading is great for looting wither skulls (as shown by DW20), knockback can be useful against creepers, quartz improves the raw damage (less effect on things like rapiers), and necrotic bones let you life steal. Personally, I tend to go with a broadsword, charging, and load it up with quartz and looting. I'll then have a cleaver with beheading when I need skulls.