Artifacts
1) Advanced Metasensory Array
This is pretty much BiS for almost every hero that uses attack speed. Huge damage rating and +1 all skills. And it's easy to find, so use it.
2) Hand of Doom
This is just as good as Adv Meta if you can get close to perfect rolls (300/300/300). If you can't, it is still decent with 250/250/250 rolls. It drops down to about slot 4 or 5 if you get low rolls (<200). Be smart about which rolls you get.
3) Xerogen Crystal
This deserves a spot on your IM if you get good rolls. Max is around 7% AS, 250+ damage rating, and the brutal stats don't hurt either. Many underappreciate how little things like a attack speed and brutal rating can push an artifact up or down.
4) Pluvian Superconductor
530+ damage rating to Area attacks (which are all of ours). Simple and effective. You can also use a normal Meta without much dropoff (see below).
5) Regular Metasensory Array
If you don't use Extremis Infused Armor (which gives 10%+ attack speed), then Regular Meta is surprisingly good. It depends how far into diminishing returns you are for attack speed. Also, remember if you are at rank 40 for your main skill, the +1 return much worse value for you. If you don't use Area as your main attack, then this will be your #4 artifact.
6) Blazing Brazier of Balthakk
800+ damage rating to burning targets (achieved with Jericho Bombardment). Great for single target, not so much for clearing trash.
7) Amulette of Agametto
Same as with regular Meta, if you aren't above 15% attack speed, you can get a massive boost with this item. Otherwise, skip it.
8) Ziggurat of Kargul
You will only lose a little DPS by going with this artifact (unless you gear for brutal, in which case you should always take this artifact). The teleport may be useful to you in getting to Doom faster.
9) Power Prism Shard
If you plan on using the leveling/farming build with Pulse Bolt, then this is a decent artifact for clearing more trash faster. If you are focused on single target damage, then PB is no longer a great option and you can leave this off.
Bad Artifacts
1) Beta Particle Mini-Reactor
110 spirit = 385 damage rating (with level 40 ARE). Now look at Pluvian Superconductor. Goodbye