Best monitor under 5k?

Metralla is onto something here. If you are forced to go with a smaller speaker that will sound good at lower volume levels (be a good tenant!), you might as well go with a speaker that is efficient and has a benign impedance load. This will allow you to use almost any amp, including low powered SET amps. Some of the lower powered tube and SS amps are very affordable and sound fantastic within their power limits.

I'm currently using the Reference 3A MM DeCapo monitors. They are a very easy load, sound very good at lower volume (as well as higher volume) and can be used with almost any amp over about 1.5 watts/channel (for most listening taste). I currently power mine with either a 3.5 watt/ch 2A3 SET tube amp or a 40 watt/ch. SS chip amp. Both sound fantastic.

Enjoy,

TIC

Tyler.....

Harmonic Precision Caravelle is a (Must) listen to monitors,before you spend your money

Acapella Fidelio ($5k+) - a little over your budget but they are the best monitors i have ever heard in terms of speed, clarity, and realism when paired with Einstein gear.

Harbeth Super HL5 ($3k+) - easy to listen to, sucks you in, very good value

ProAc

Westlake

I believe it's hard to go wrong with the PSB Stratus Mini. They have an 86 db impedence and are a 4 ohm load and thus require a powerful amp, but are neutral to somewhat warm, sound good at low volume, and have more clean bass than a stand mounted speaker has a right to. And they are much less than 5k.
John