You could get into the Powersnakes Black Mamba or the new Powersnakes Viper even for what you are willing to spend. I had some Harmonic Tech AC 11s for my Pass amps and I found that the stock cords sounded better, if you have a bright system the Harmonic Tech might help, but for me they sound dark and slow. If you can afford it, nothing that I've tried even comes close to the King Cobra, it is laughably better than anything I've ever tried. You might check with Anthony he is very knowledgable and has great prices.
Power Cords
I am looking for a new power cord (two meters long is sufficient). I would use it on a Adcom GFP-750 now and possibly move it to a Classe CA-201 amp later on if I get a second cord. I have heard a lot about the MIT Z Cord 2, some of the Synergistic research cords and all of the Powersnakes. I would definately buy used and am willing to spend up to $700 (though I wouldn't mind getting something less expensive). Thanks for your thoughts!