Wrath of the Lich King has added some wonderful crafting changes, from new abilities to better, more efficient systems.
Blizzard's intention is to move us away from feeling that we have no real choice when selecting a profession. 'I am a cloth-wearer, therefore I must take up tailoring' is a thing of the past.
Each profession has bulked up its profession-only benefits, as well as fun items and marketable goods, to the point that your choice can be more properly swayed by what you would like to do.
While you are leveling your chosen fields, you will notice many interesting recipes popping up at fairly regular intervals, giving you small goals to look forward to and work towards.
This week, I will be showcasing the highlights of Leatherworking and Blacksmithing, including when you can train these recipes, which factions have what you need, and what it is that makes you unique and important.