DC Ares: I find it nearly impossible to measure a lot of these types of DC characters...
Dr. Strange: 10
Immortal Hercules: 10
Wonder Woman (pre52): 9-10, I still believe Immortal Herc is stronger and more durable, though she has a speed and mobility advantage with her flight...so I think they're pretty much equal overall.
Superman (pre52): 13
Captain Marvel (Billy) (is there really a difference pre52 vs post? Besides some electical powers?): same as Superman
Orion: 15 (yes, I put him more powerful than Superman. I think Supes and he are equal in strength and durability, and Supes has a speed advantage, but Orion's Astro Force versatility and mother box gives him a measurable overall power advantage.
Doomsday: DOS 13, Overall equal to Superman...stronger and more durable, but without EP and true flight
Darkseid: 17 estimate...I think he's a peer to Superman and Orion physically, and his OE is a little more effective and versatile than the Astro Force...and generally he operates at a higher level, but is well within striking distance of Superman and up
Green Lantern Hal Jordan:10, higher lows than Dr. Strange, but lower highs, I think he's generally operating on about the same level
Ganthet: either 10 or 100....all over the place
Crisis Anti-Monitor: I'd first have to measure Supergirl Pre Crisis and add about 20%...
Mongul the senior: 10
Mongul the junior: 9
Orion has never been stated as equal to Superman or more powerful than him.
Superman is definitely not lower than Surfer or Thor in power and would never be shown as such in a comic.
Darkseid is at least 30. He is in similar class as Galactus or Odin.
Hal is at least 15, going above that currently.
Ganthet is at least 25.
Anti Monitor is 100. Pretty much abstract level of power. Supergirl showing is akin to Thor almost killing Galactus. Anomaly that is not at all his usual power levels.