Obviously any advise you'll get is likely to be biased.
Personally, I'd go for the 920, but of course the Nexus would be a good choice too.
If you do go for Windows Phone, definitely go for the 920. The exclusive apps and the camera can't be ignored. Of course the 8X looks nice and is smaller and lighter, but with Nokia you know what you'll get. Constant updates and added features you won't see on other phones.
As for the apps, Instance (formerly Itsdagram) is excellent. In my opinion it's no worse than the official app on Android. Pandora is said to be excellent too, with some people saying it's better than on the other 2 (I couldn't tell you myself, because I'm not in the US so I can't use it).
Words with friends I don't play so I can't help you there. I'd have a look at it, but there's no free trial. The reviews are indeed horrendous though.
Anyway, I suggest playing Wordament instead. Best word game ever. And it's free and has Xbox live achievements.
Thanks for the reply! I was looking hard at the 8x but you're making me reconsider.
About to turn in my 920 for repairs... gets hot, system locks and screen freezes, sometimes with green pixels or the whole screen gets like a green filter... Also the screen dies and when you press the power button the screen is black but the 3 buttons on the bottom lights up. Hard reset and total reset of phone didnt work eighter.. anyone else had problems like this? Started like this for like 2 weeks, then I had no problems for around 3-4 weeks and after I charged the phone 2 days ago it just started again..
Want to love it but its so hard when you cant trust your phone:/ Shouldve gone for Samsung..
I'm very worried about this.