Seeing as if you continue playing this game and would like to participate in more of the end game content, you could pretty much accept the fact that you are taking all your combat classes to 50. I guess its all about the order you take them in. If you are thaumaturge 50 you definetly need conjurer 50.

After taking those two to 50 just randomly pick another class and take that to 50. Having each class at 50 is not an amazing feat and pretty easily obtainable with some a little more than casual play. Each DOM/DOW that you have a 50 makes you that much stronger in each other class.

As far as crafting is concerned, ME personally if i was in your shoes knowing what I know now, would just stick to leveling all your DOM/DOW to 50 first. If you get bored grab a handful of leves from uldah (GSM/WVR/ALC) for kicks.

My two cents... hope it helps.