[Nexus 5 General] aeoveu:
I think I found the culprit: the new Google Play Store - the one where Paypal support and bigger buttons were introduced (that was the tl;dr, but you may want to read on).

After resetting more than a couple of times (yeah - the most I've done in such a short span of time with ANY phone I've owned), it turned out to be the new version of the Play Store... I'll tell you how I reached this conclusion:

Back up a week or so, Android Police leaked a new version of the Play Store. Me, being in a hurry to get the greatest and the latest, downloaded the APK and installed it. And also, circa that time, Play Services seemed to drain like there was no tomorrow (I didn't correlate the two together until last night).

Uninstalling apps didn't help (as I stated earlier). Doing a factory reset didn't help either (because - what I usually did after a reset was install ES File Explorer, Titanium Backup and the new Play Store, THEN restored the rest of the apps, if I did) - and leaving it on idle created the drain for no apparent reason (I even decided to not update the system apps and not restore ANY app from Titanium last night, and there was still a drain). That drove me mad (just like it was driving everybody else mad). I knew it's not ES File Explorer nor Titanium cause I had these apps long before and never gave me an issue.

Also, since Google Now has its own nlpwakelock process, I ruled out that possibility (correctly). I even turned Now off and it didn't improve anything. I thought perhaps some shady app was present which was indirectly requesting for location from Play Services - but when I didn't install any app that required location access, it still drained the battery!

This time - I decided to not update ANYTHING (including the system apps) nor install the Play Store manually (using the APK). I waited for a few hours, and saw that there was no drain (read: drain was on normal levels). I proceeded to updating the system apps, and it seemed to respond fine. I then installed a handful of apps (through Titanium Backup) and saw that the drain was still stable, and later, restored almost all of the apps that I wanted. The drain, as of a few moments ago, is 0.7% per hour (and ~8 min awake in a duration of ~3 hours)

I still haven't installed the new Play Store apk and my phone appears to be sleeping fairly normally (Wake Lock Detector reports awake times of 4% - which is not the 3% that I usually get, but it's better than 20% or some other blurb!). And - my question is - how many of you are using the New Play Store that have the drain?

Another reason why I feel this was the culprit is because usually, the Play Store is rolled out just as fast as Play Services. While I don't have a contact in Google, updates usually do not take a week or so to roll out (cause the Play Services update came after and finished rollout quicker), so perhaps they saw that there's a bug? These are my thoughts.

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On a completely unrelated note, the new Google+ update seems to be a frigid prick. I don't use G+ (except for the auto photo backups) and the new update now has TWO options for photo backup:

(1) Google+ Photos, and

(2) Google+ Auto Backup (or some verbiage like that).

I turned off (1), turned off "Google+" sync, and left (2) enabled.

And after a few hours, both (1) and Google+ sync would be checkmarked (i.e. turned on!). Not sure how much awake time that's taking - but at least it's not like the Play Services drain. In the phone's built-in battery page, the awake lines are sporadic (not clustered like they were - just random) and I think that's possibly cause of G+, or perhaps the Google Searches being cached into the phone or something else.