Whats the acceptable aatire for the nice Tapas/Cafe bars in Madrid and Barcelon? Casual T/Jeans or Sportcoat etc? Do people dress up or down these days for the food-hopping-nightlife (no clubbing - just food/wine bars!)? thanks!
Casual is fine. Khakis are never out of place, but lots of people wear jeans and sweaters, too. Most often, I saw men in button down shirts, as opposed to t-shirts, but I saw plenty of t-shirts, too.
Tapas bar crawling is a sport which crosses the social divide. However you are dressed, you will find some bars in which you feel over/under dressed and some in which you feel comfortable. Obviously, it is easier to dress down a sportscoat and oxford (just take of the jacket and loosen the collar) than it is to dress up a tee-shirt and jeans combination. In any event, don't worry about it. Most tapas places are about the food, not the attire.