I don't like to add 18% to my bill either; I hear you!
For quick service, I'd look into the "wharf" at DCA--it's kind of like a food court, so every member of your party can get something they like. I've heard mixed reviews of the Chinese restaurant there (I got the beef and thought it was just OK, but some people love it). But I liked the place where you can get soup/salad in breadbowls (you might want to get the breadbowl on the side and eat some later; there is a LOT of bread). And my travel companions liked the Mexican food there; I think my picky-eater friend liked it more than Rancho del Zocalo in DL.
In DL, I'm rather partial to the Bengal Barbecue in Adventureland, though that can get pricey. Great tip I read that could be especially good for a large party--buy some bread (with butter!) in DCA at the aforementioned bakery/bread-bowl place, and then eat it with some skewers. You can get a loaf of bread for not that much more than a (small) side of breadsticks at the Bengal Barbecue. And IMO the bread tastes better!
I haven't been yet, but the Hungry Bear Restaurant in Critter Country's new menu looks excellent; it's top of my list for places to try on my next trip. The new eateries at DCA (near-ish to the Little Mermaid ride and Goofy's Sky School) look good but a bit pricey. For value, the Troubadour Tavern in Fantasyland looks pretty good.
Rancho del Zocalo in Frontierland is decent, and some people love the Plaza Inn for dinner (a lot of couples suggest splitting the chicken entree, but I don't like chicken on the bone so it's never appealed to me). Others love Redd Rockett's Pizza Port in Tomorrowland. (If you go to a "buffetria" style restaurant like Redd Rockett's, I do suggest that you make sure the food looks fresh...I don't THINK it made me ill, but I did have a piece of veggie pizza there that looked like it had been sitting too long, because I had my heart set on veggie pizza, and I did feel slightly ill the next day. Just saying, don't be foolish like I was....

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Several of the places in Downtown Disney have a limited "quick service" menu. The items there tend to be cheaper than their full-service counterparts, AND no gratuity! We ate at Ralph Brennan's Jazz Kitchen carryout...I wasn't impressed by my chicken strips (though the servings were huge!) but the beignets were good, if you like greasy fried things. (I do.

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If you haven't seen it,
http://allears.net/dlr/din/menu/menus.htm has more menus; just look at the "counter service" ones.
Have a great trip!