Note: This is a post in progress regarding powerleveling of Engineering. It is currently changing as I finish my leveling experience and may not be chronologically consistent.
Well, I've given up on Alchemy. Thrown in the towel, the vials and flushed all of my reagents down the toilet. Actually, never seen a toilet in WoW. I suppose I will need to trek to Un'Goro to relieve my toon some day.
So, I've powerleveled engineering, which went very well according to the guide (just remember to go back to the trainer after each step). The entire thing can be done in Ironforge, which is very nice. There is also a guide from Ten Ton Hammer, that helped ease the post-300 skill level.
Currently, I'm 300, which took about 6-7 hours and somewhere in the neighborhood of 800-900g. Overall, the experience was quite doable and I'm looking forward to obtaining some of the rare items with lowbies or as a soloing project. I've always wanted to have a soloing experience, but never could come up with a justification for soloing in BRD or Gnomer. Now, I do.
As such, I think changing a profession is a great way to get out of the pre-Wrath doldrums for a casual player, especially if your class has some soloing potential or you like PvP. For a druid, we can't benefit much from the guns, but everything else is quite usuable indeed. Just remember to keep a gathering profession, this is the casual gamers path to money making.
As for the answer to the post-title question: Gnomish Engineering. Yes, I've gone Gnomish, as I plan to play a healer in end-game and the crowd control options available with gnomish seem quite nice to me. PvP will also be a much bigger part of my play in Wrath, as it takes up much less time. Being an annoyance with the Mind Control Cap against a Grand Master Greifer should be a lot of fun.
Anyway, I'm off to gather up the cool engineering stuff, while taking my time and enjoying the scenery along the way. It appears that I will be taking a tour of the old world.
I had the money making scheme well dialed-in with alchemy (make a transmute every day), so finding the niche and markets for Engi stuff should be fun too. For all you economics lovers, changing professions is a great fun.
On the Gnome State Engineering Curriculum are:
101 Trainer Gizzes
210 Gnomish Stuff
376 The WotLK Stuff
501 Rep Stuff
I will keep a log here of my success in training and report on the utility of my new gadgets.
Any Engineers out there with suggestions or items I've missed?