Which upgrade should be my priority?

I'm with the others. Lets reedit.

1) Speaker stands ($50-whatever)
(wood can be nice if done well, if you do metal it must sand filleable. I've used the Cinder blocks myself, I feel like a tweek saying this, but turn them so the holes are facing you--should minimize diffraction more)
2) Acoustic Treatment (<$75)
3) Cables (DIY)
4) Deadening speaker cabinets w/ dynamat (<$50)

These'll get you mileage until you get your better components. Decide which ones you can use in your system since you didn't specify your speakers or other things. Look up the older threads like, "best cheap tweek" "best inexpensive tweek" etc.

I, too, resoundly agreee with Natalie. I like the roof analogy he used. Stands were mentioned, and I know, from experience, and the science of resonance transference, how critical the stands are. Infact, they are as important as any of the other components in your system. Poor stands have a deleterious affect on your music, that many times is attributed to other components. It not until you have killer stands that you truly hear the difference. This is what has happened to me. I own, now, a speaker support system by Star Sound Technologies (Audiopoints). You've heard of Nordost Valhalla cables? These are the equivalent in the speaker stand arena. I'm going to do a review, soon, because I am so truly amazed what they are doing for my system. They are based on a completely differenct science than all the other stands out there. I know this is hard to believe, but the stands you all know and love, (I won't mention any names) are doing, regardless of how costly, more to degrade your music. Cosmetics seem to be the most important thing to many manufacturers, with dampening as their main goal. Star Sound Technologies believes that vibrations are good. Music is a vibration. Just give these resonances a place to go. Cosmetically, by the way: Beautiful. Like nothing you have ever seen. This is cutting edge stuff and truly remarkable. Stay tuned. I'm not a shill for Star Sound, just a very happy audiophool, who wants to spread the word about something cutting edge.

Hi

PLEASE....PLEASE..... Change your speaker cables! I cannot bare to think about what you have ARRRG. Go to Home Depot and get some 18 Gauge Bell type wire use three straight wires per conductor.
Make your own speaker stands and save some money for a tube amp.
For less than 500$ you can get a modified Dynaco tube amp (here on the GON) that has dam good sound and is quite cheap and easy to maintain.

Good listening

mike

there are some AQ Slate speaker cables on sale at AudioReview for 60% off. 10ft pair for about $100 w/shipping, I think. The only bad part is theyre terminated with spades and my receiver(Yamaha) and speakers (PSB Alpha)
can only accept pins. So which should I get speaker cables on sale or speaker stands?