SideBar is awesome.
I've been here three times for the world famous #buzzcation events (follow @buzzcation on Twitter). I'd be here more often if I lived closer.
The exposed brick, dim lights and sleek couches scream "ultra lounge," but you wont find any pretentiousness or 30K millionaires here.
The beer selection is great. They have several wheat beers (my favorite); if you ask for an orange slice, you'll get a HUGE slice.
I don't know what the atmosphere is like during non-special events, but the place is very laid back, and pretty cozy. They accommodate large groups well.
Kudos to Josh, the owner, for supporting the PHX community.