Best used floor standers up to $1300

1. Klipsh 5.5
2. Zu omen
Both can get loud and sound good.

PSB gold

Magnepan 1.7's can be had (and cherished) near this price...

Klipsch KG 4's can be had for about $300 in good condition.
Can do a Crites Titanium Tweeter upgrade and a crossover rebuild for next to nothing.
Blow the Roof off on Mini Watts, Not amp fussy, great bass and detail, plus they sound Great with all types of music.
Bullet proof. Not position or room fussy.

I've had a pair of Usher CP-6311 floorstanders, for about five years, that I've been really happy with, and not yet found anything at that price range I've liked better. They were $1200 if I remember correctly. They can go loud and still sound musical, fairly revealing, a bit laid back, never too in your face, maybe a hint of harshness if you really crank them. The quality of paint finish is great too. Their one big trade off in my opinion is lack of bass, more like what you'd expect with a monitor.

Probably anything from Usher around the $1k mark is a safe bet, if their taste is your cup of tea, and especially if you can find one with the beryllium tweeter at that price. I'm just getting around to upgrading from mine, and I feel I have to look at speakers costing 5-10x as much to get "significant" improvement, which is a great compliment to the 6311's I think.