Pair of good quality professional powered studio monitors. Here's some info from their website.
Designed for superior performance in both home studio and small professional mix rooms, the Eris Studio 5 combines flexible connectivity with sonic accuracy that puts it a class all its own.
The custom-designed EBM (Elliptical Boundary Modeled) waveguide provides superior high-frequency response and wide 120-degree horizontal dispersion to create a broader sweet spot. Narrow vertical dispersion reduces reflections from your desk, and a silk-dome tweeter ensures snappy, accurate transient reproduction. An elegant new enclosure design improves the waveguide performance so you'll hear the finest details in your mix.
These have only ever been used in my non-smoking home studio and work perfectly. Power cables will be included. These currently go for $269 each + tax