Because of a fortunate job with porting our apps to Android I have the Nexus 7, Asus Transformer, Kindle Fire HD and a few others.
The Nexus 7 does not have HDMI of any kind so that knocked that one off your list. But it is a FINE tablet.
I have the Asus TF300T Transformer but it fails your micro usb requirement. It also has one speaker.
Where did you read the Nexus 7 had HDMI?
And about gaming. It's tablet gaming, nothing like a PC so be sure you are into that.
Been doing unrelenting research on what tablet to purchase by Christmas and it's just leading me round in circles. Review after review, youtube video after youtube vdieo and still have not made a definitive decision. At the moment, I am thinking "Nexus", it seems to have all the main features that I want (Hdmi connectivity, stereo speakers, good gaming tablet, hi res, micro usb) Unfortunately 2 things wrong with that....1) Unavailable in Ireland till god knows when, and 2) some reviews have said it's not all its hyped up to be.
Anyway, also looking at the asus 700, the nexus 7 (strong possibility) and...well....the ipad mini? Any advice from anyone with knowledge on any of these. God knows, you will have more knowledge than I do.
Would greatly appreciate some advice