I’d agree with signman on the steak houses – Pappas is by far the best although III Forks is good. If you go to Pappas and they happen to have the lobster bisque – indulge! I don’t know how they do it in the middle of TX but it is really good. Bob’s has been there FOREVER and some of the local celebs can be seen there. Also agree on the two diners – Mama’s Daughter’s has the best chicken n’ dumplings and The Mecca has been there since before dirt, and so have the waitresses – be prepared to wait but they turn ’em fast. Good Mexican – there’s a little place in Coppell (just north of the Cowboy’s training facility) called Guerro’s that I highly recommend. Another place that’s a regional chain but darn good is Abuelo’s. Pappacito’s is pretty decent also. Believe it or not there is also the most awesome Greek place on Preston Road in Plano called Zorba’s. I would also recommend looking at guidelive.com they have pretty good reviews and listings. For BBQ I’m a fan of Dickey’s (a few locations around town) but many feel Sonny Bryans is the true BBQ. I think Dickey’s has better (leaner) brisket.
Have a blast!