How upscale do you want to go?  On your dime, or the company's?
The Regency on Park Ave and 60th is one of the preferred spots for LA music/film execs.  The W on Lexington Ave.  Four Seasons on 58th Street/off Park.  The Plaza, maybe.  For dirt cheap, The Wellington on Broadway and 55th.  But it's touristy, not upscale.