Some good choices already, of course, and Ron Carter and NHOP are among the tops. I think of all these guys as great contemporary bassists, although I am not sure all meet your Ray Brown criteria, per se.
Christian McBride -- Live at Tonic, Kind of Brown
Eric Revis -- Tales of a Stuttering Mind; Branford Marsalis Quartet (Metamorphosen, Braggtown, Requiem, Contemporary Jazz); Jeff Tain Watts (Citizen Tain, Bar Talk)
Matt Penman -- SF Jazz Collective
Greg Cohen -- Ornette Coleman Quartet (Sound Grammar); John Zorn/Masada (multiple); Tom Waits (multiple)
Harald Johnson and Mats Eilertsen -- Tord Gustavsen Trio