1. BS and 2. Eng are the hardest. Like someone already said, "Need to use the mat to make a mat" but then you still need the original mat........blah!
3. LW thru 300 is annoying, then the mats (on my server get expensive)but the process is easier
4. tailoring and 5. enchanting (usually go together and they are Gold sinks)
6. Alchemy and Inscription are almost as easy as gathering professions.
7. Skinning (what? I have to kill and now with Group Loot...someone might steal my Skin!) <no xp gain= grrrr> where is group skinning?!
8. Mining and Herbing = xp gain
Archeology is MUCH easier then it used to be, pays pretty well and offer great XP and sometimes cool stuff) but it's also a little time consuming and frustrating when it sends you away from where you want to dig.
Cooking (darn it, I forgot to level it during Thanksgiving week) can be expensive or time sinks..
First aid = farm the mats or pay the price but right now most of my cloth is going to my Monk's Tailoring
I'm not a "pro" raider so most of my toons have the gathering profession to go with the Crafting. However, when I started alts that were repeats I chose more raid conscious crafts like my second hunter is an eng/lW and I have a second priest that is alc/ins and my monk is tailoring/ech. It's expensive to level and a lot of toon hoping happens but even tho they are not at maxed level , I can see they are More raid "ready".