Enduringly popular with Dallas' movers and shakers, Al Biernat's has been a neighborhood stalwart for over 15 years. And there's as much buzz around the celebs who dine here as there is about the food. The attraction is a combination of faultless service, an extensive wine list (650-selection) and a menu that keeps on giving. The main event is the meat; all impeccably-sourced and flawlessly prepared. The selection runs the gamut from wet or dry aged N.Y. strips and cowboy cut ribeyes to prime rib, buffalo and melt-in-your-mouth Japanese A5 Kobe.   But the menu doesn't limit itself to beef alone, diners can also tuck into everything from fresh seafood to lamb, wild boar, quail and even Petrossian caviar.