Right now I have Engineering and Inscription. No way I'm giving up Inscription (+61 spell on the shoulders and scrolls of recall ftw). As for Engineering, there's not a ton of very useful things for buffing my character. Made nitro boosts for my PvP boots for a quick getaway and I think we all used it for the epic goggles. But now that I'm past that level, I'm thinking about dropping it and starting Jewelcrafting. Those nice Dragon gems look mighty tempting to me. Is this a good idea or should I just stick it out?

Being the number cruncher that you are, if you're looking to maximize numbers even more I'd say yeah, drop engineering and pick up jewelcrafting like you mentioned, or enchanting for the ring enchants. Engineering is the "fun" profession with only a few things going for it. One of the things is the engineering goggles, which once you're raiding naxx or higher are easily outshined. The various armor enchants it has to offer are not worth it in the long run. Theorycrafters have proven time and time again that the extra rotation of say the hand-mounted rockets isn't worth it. In fact, theres only one enchant out there now that would be worth it, and thats the on-use haste boost for gloves. Engineering trinkets are novelties at best, and atm have nothing worth using in a raiding environment. The Mechano-Chopper is also cool, but not BoP, and we have plenty of other engineers in the guild.

So, short and simple? Yes, if you're looking to boost numbers, drop engineering. If the grind for a new profession really isn't your style though, it won't hurt you to stick it out.

Blizzard had a 6000 (!!!) post long thread on engineering a few weeks back which included a lot of meaningful Blue feedback. The gist of the post is, they are happy with engineering and we shouldnt expect any buffs to it. Frankly, JC will be better for you even if you only lvl it for the extra gem slots

That settles it then. Guess I'll be PL Jewelcrafting this weekend.

Sanch, in case you check this I would recommend making the switch as well. Engineering was fine for leveling and the mount was nice, but now it just isn't useful for PvE at all. JC's get the cool uber-gems at 370 and at 400 you can make a nice +hit trinket that you can gem for even more spellpower.

Managed to PL it this weekend with some nice help from Muri and cleaning out one of my bank alts. Should have the nice +32 spell gems equipped before we head back in to Ulduar.

I know we're bringing this conversation to two places now, but it keeps juggling around lol. I discovered last night something very interesting: they added new trinkets to the Wintergrasp quartermaster! All the new trinkets are ilvl213, and just like the previous trinkets, they only cost 25 WG marks. Of the new trinkets, some of them have some VERY worth while stats, if you're struggling with PvE drops:
Titan-Forged Rune of Accuracy - 95 hit rating
Titan-Forged Rune of Audacity - 111 spell power
Titan-Forged Rune of Alacrity - 95 haste rating
Titan-Forged Rune of Cruelty - 95 crit rating
Titan-Forged Rune of Determination - 190 attack power

All the trinkets have the "on use" effect to free you from stuns, fears, roots, etc. just like the insignias/medallions of the alliance. While that might not be that great for PvE, the initial stats on some of those trinkets is pretty amazing. The hit one alone is pretty nice if you're looking to reach the hit cap quickly. Just some thoughts, in case you don't want to drop engineering Sanch lol.

Actually, I've been using the audacity trinket for quite awhile now for both PvP and PvE. I use the trinket during stuns and snares from trash mobs and some bosses.

It would also be a good one for affliction and any caster build that scales better with spellpower. I've considered the Alacrity one as well for haste since my build favors that a bit more.

As for JC, this is the craft trinket I was looking at Twilight Serpent