KLNC (home of the DFW Wing & CWAM) has both a warbird discount and a great restaurant.
KAPA had a discount at both Signature & Denver Jet Center for warbirds and all 3 FBO's on property always had great staffs no matter what you flew.
KBJC has always been great at both FBO's. Don't know about discounts though. Never flew in with anything more than a Cessna or Piper.
Others that I've had good experiences at -
KDTO
KFAR
KRAP
KCYS
KTYS
KGRI
KGCK - Excellent staff, huge airport, absolutely nothing going on at the airport for that much airport.
KABQ - Went in during a visit by Fmr. President Clinton and had an excellent time at Cutter. Don't remember paying any fees either when I bought a half tank of gas for the 182, but their fuel prices tend to be a bit high due to them having to truck in all of their fuel ($6.35 for 100LL as of today).
Think that's about my list. I've been to several other small airports that loved warbirds, but sadly, most have either closed or changed ownership since, so I can't tell you whether they're good anymore or not.