An extra socket each in your wrists and gloves, each with a [Brilliant Primordial Ruby], gives 320 Intellect. However since another gem (such as [Smooth Sun's Radiance]) might be even better, Blacksmithing can give somewhat more benefit.
Synapse Springs give 1920 Int, for 10 seconds out of every 60, for 320 Int on average (varies slightly in practice). Has potential to slightly outdo other professions since you can time the use to be most efficient.
500 Int to bracers in place of the usual 180 Int gives you 320 Intellect.
Mixology (with your [Flask of the Warm Sun]) will give you 320 Intellect.
160 Int to each ring gives 320 Intellect.
520 Int/100 crit to shoulders in place of the usual is a gain of 320 Intellect.
Lightweave Embroidery gives 2000 Int for 15 seconds, 20% proc on damage, 60 second cooldown. The average benefit with perfect procs is around 500 Int, minus the 180 Int you usually have on your cloak, for an increase of around 320 Int. This is slightly reduced due to delay on the proc, but increased since you get a proc at the very beginning of the fight, so the end result is similar to other professions, but with a little variance.
2 [Brilliant Serpent's Eye] in place of 2 [Brilliant Primordial Ruby] gives 320 Intellect. However, since [Brilliant Primordial Ruby] may not be your best gem, the gain is slightly less. In addition, Jewelcrafting may grow weaker when epic gems are introduced.
Gathering professions are weaker:
now gives a haste cooldown via Lifeblood. At 2880 haste for 20s every 2 minutes, it averages out to 480 haste
gives 480 crit rating
provides 480 stamina, but no DPS gain