I know this has come up before, but I couldn't find it through the search function.
In no particular order:
1) Pizza at Spago (Caesar's Palace Forum Shops)
2) The In-N-Out Burger at Tropicana and Dean Martin.
3) Binion's Ranch Steakhouse (quintessential old Vegas menu and prices).
4) The 24-hour $5 chicken-fried steak special at Longhorn Casino, Harmon and Boulder Highway.
5) The 777 Microbrewery at Main Street Station, Fremont.
6) The $2 shrimp cocktail at Golden Gate, Fremont.
7) Any Roberto's for their Mexican food. (They're all over the place.)
8) Hofbrauhaus Las Vegas, Paradise and Flamingo
9) Studio B Buffet at M Resort (way way South Las Vegas Blvd.)
10) Spend the $80 per person for Sterling Brunch at Bally's (The Strip, Sunday only)
11) Stock up on "in-room noshes" at International Market, Tropicana and Decatur (best foodie market in the valley).
12) Amazing pizza at Settebello, "The District", Green Valley. (Certified by the Naples Pizza Cartel -- I don't know the name of the group. But only a dozen or so pizzerias in the US have this certification.)
Not a bad list assuming the OP has a car.
On the strip, there isn't a lot of great deals anymore. That is unless things have changed with the tanking economy.
Planet Hollywoods shopping mall (easy walking distance) use to have a decent selection of reasonably priced places to eat. NYNY's good court area has some surprisingly decent places that aren't to expensive. You might check the casino coffee shops for specials. The last time we were there they were underwhelming but, things could have change in the 16 months since our last visit.
If you can get up north to the Stratosphere, they use to have a decent selection of restaurants reasonably priced. We rarely go that far north anymore so I'm not certain on their current status.
Chin Chin's in NYNY use to be a reasonable a good Chinese restaurant. America in NYNY use to serve a decent breakfast but, last time we where there I wasn't overly impressed. The menu had been cut back, prices were higher and the service wasn't all that great. The Cafe in the Monte Carlo use to serve a decent breakfast at a reasonable price.
If money is a concern, I'd stay away from MGM. Everything from their coffee shop to their Mexican restaurant is WAY overpriced.
I am not a big buffet fan but, Bellagio and Paris had very good buffet's the last time we ate at them. Pricey but they were good. Tropicana use to have a reasonably priced buffet that wasn't all bad. It wasn't great but they did have a variety of choices and a decent price.
There is a Cheesecake Factory in the Forum Shops at Ceasers Palace and a Grand Lux Cafe in the Ventitian that provide reasonably priced good food. Chain restaurants yes but, it's consistantly good food at reasonable prices.
Downtown has better deals than on the strip but, you have to get there and it can be a little seedy. It's not our favorite place to just hang out. Many of the off strip casino's offer good value for restaurants. South Point (5 miles south of Mandalay Bay) has a nice selection of reasonably priced restaurants and good gaming odds. There's a little outdoor shopping district just south of Mandalay Bay (can't recall the name off the top of my head) that has a Claim Jumper restaurant that I really like (again, a chain restaurant but still very good). If you can get down to the outlet mall south of the airport there is a decent Italian restaurant called Bootleggers that's pretty good and was easy on the wallet last time we were there.
There is also the Peppermill restaurant up on the north end of the strip by the Riviera many people swear by. Prices are good and it has the old Vegas feel to it but I've never really cared for the food quality myself. It's still worth a shot if you work your way that far north.