Best Used Solid State Amp for less than $5000?

I own the Ayre V-5x - and I second Noble110's reccomendation, it is a wonderful amp, but you may also want to check out the SimAudio W5. I think both of these amps can be had around $3200 used, purchased new, the W5 is $5k (I think) and the Ayre is $4500. If the Hales are a difficult load, the W5 has a little more punch.

The Goldmund Stellavox amps are simply sunning in every sonic respect. They sell for $3600 to $4000 new, and are worth at least twice that amount. What about these little amps makes me say this? For one, they are ultra fast amplifiers, with clean and uncluttered articulation of the most demanding material. They have a solid bass, and a neutral to slightly forward midrange with detailed highs. After 100 or so hours of burn in, you get the most amazing layered and 3 dimensional soundstage very much like a quality tube amp such as the better Cary or CJ amps. Yet, these 200w RMS monoblocks are only 10lbs in weight and about the size of a hard back book. I hate to rave about anything in the audio world, because I have been around a long time, but these things are worthy of some praise.

Plinius SA-250IV is awesome !!!

I still believe Aloia amps(15.0I) are one of the best buys in audio. I've seen them for as low as 2k

I see some McCormack DNA-2 Rev. A and LE amps for sale under $5k.