can we have actual patrons singing drinking songs when we enter them?

I hope so. I wouldn't mind a bar brawl or two on random occasion. I want to almost smell the tavern when I enter it. (not literally but figuratively speaking)

Hopefully. There is a lute player. New Vegas had those singers in Aces too.

I'd like to see a more lively bar. Taverns In past games have been really boring/useless. They are just there, to be there.

It sounds like they will be the place to go for the latest rumors, and after work a lot of town folk will head there to hang out. I'd like to see them make it so that you hang out at taverns, play drinking games, buy rounds of beer, whatever, and your approval rises with the towns folks who are there. Give me something to do, and a reason to do it, and I'll hang out at every city and town bar!! Cheers!

Around 1:32 in the trailer where the character does a stealth attack on a person in a tavern. You can clearly see someone playing the lute.

And seeing as they are supposed to be a vital part of the game to hear gossip, lead you to quests and what not then I'm sure they've been really worked on.

Apparently taverns can now be used to find information on quests and such, so having a more realistic atmosphere would be nice. Maybe even people approaching you for a simple chat from which you can glean details for quests. And of course outside of the light cast by the hearthfire there is a shady skooma dealer.

I wouldn't doubt it. Skyrim will be utilizing taverns a lot more, and Bethesda has said that they're putting a lot more work into them.