Android

Sony Xperia ZL CyanogenMod 10.2.0 Release Android 4.3.1

4.4.2. It's feels a lot smoother than previous versions actually. It also spawns a kitten near the phone every 10 minutes.

4.4.2 Nexus 5 and 4.4.2 Nexus 7 (2012)

Here is a usefull link for you :)
http://www.androidpolice.com/2013/11/02/november-android-distribution-numbers-jelly-bean-now-on-more-than-half-of-devices-gingerbread-stubbornly-holding-on/

4.2.1, Asus TF300T and 2.3.3, LG P500

Samsung Galaxy S2 GT-i9100, official Samsung 4.1.2 ROM

4.4.2 and 4.0.3

4.1.2 Xperia P

JAVA

Stock ICS 4.0.3

Still Gingerbread.

4.2.2, probably going to upgrade it to 4.3 soon.

4.0.3

4.4.2 on the Nexus One, about to upgrade to Kitkat

4.2.1 MIUI 5

2.3.7

4.4.2 Nexus 4

4.1.1 on Galaxy S3

4.4.2 Nexus 5

4.2.2 HTC Desire HD

4.3(Stock) Galaxy Note II
4.3(Advanced Stoc ROM) Nexus 7 2012

4.4.2

On a Nexus 4, I'd really like to upgrade to the Nexus 5 or a Moto X though.

4.4.2 Nexus 5

4.4.2 Nexus 4

I still use 2.3.6, but I'm probably upgrading to the latest Cyanogenmod soon. Just fyi, you can check http://developer.android.com/about/dashboards/index.html to get a good overview.