Some recommended hotels: these are in downtown New Brunswick, a few minutes walk from lots of good restaurants etc.
Hyatt Regency
  in downtown New Brunswick.
The Heldrich
  in downtown New Brunswick.
Some less expensive hotels: these are outside New Brunswick and require a car to get anywhere.
Holiday Inn
  4701 Stelton Rd, South Plainfield.
Radisson Hotel Piscataway
  21 Kingsbridge Road, Piscataway
Motel 6 Piscataway
  I-287 at Stelton Road