I'm in Barcelona... Please No More Tapas!!
There's a small bar/restaurant on Las Ramblas called Vienna, and they have a sandwich for 6 euro that the NY Times said is the best sandwich in the world (it's pan amb tomaquet con pernil iberico, i.e. bread with tomato and iberian ham). It's really good, but not a whole meal. They have a lot of small sides though, and a 200 ml of Codorniu 1551 (cava) for like 2 euro. You can make a good lunch out of it if you combine things.
Good moderate priced restaurants not specialized in seafood:
Senyor Parellada, c/Argenteria
Cardoner, c/Ample 46
Ample 24, c/Ample 24
Cafe de L'Academia, c/Lledo 1
L'Agut, c/Gignas 16
Can Calleretes, c/Quintana 5
Can Luis, c/Cera 49
Foxo, Gran Via del es Cortes Catalanes, between c/Agricultura and c/Cantabria
Goliard, c/Progres 6
Just came back from Barcelona, and I know what you mean about needing a tapas break!...there was a pizza place called San Marino on Carrer de la Ciutat (number 121, I think) off Plaza Jaume. Totally unassuming place (if you blink you'll miss it), and from the front doesn't look like there's a dining room. Just pass the pizza chef on your right and continue down the hall. It certainly won't win any design awards, but it was very inexpensive pizzas on thin crusts that are the size of a dinner plate. Makes for a nice change.
I believe they close between about 4 and 8.