FURMAN, PS AUDIO, ISOTEK??

you have nice gear...if you can borrow some pieces and hear how it sounds you'll be way ahead of the game. If you do not have a dedicated circuit for your stereo then I would do that first and add a power cord to the DAC....if you have fairly clean electricity you might not need a conditioner. I use an Exact Power EP15A which holds the current at a steady 120 volts and protects against surges and brownouts.

The very wide and disparite opinions expressed about power conditioners of all sorts makes me wonder if you can say that they will upgrade your system in any general way. There are exceptions to this if there is a particular problem. For instance power regenerators for people who have power brown outs and peaks who wish to stabalize their power. Other specific examples are out there I am too lazy to list the ones I can think of. So unless you have a very specific issue invest you upgrade money eleswhere.

You didn't mention power cords. What do you have? I would address this first.
And how much are you prepared to pay for how much improvement? Generally speaking, to get some control over the incoming current is quite expensive. But still you could improve the situation for a few hundred dollars if you wait and buy used.

Thanks a lot to everybody, it has been a great help.
The conclusion is going step by step so I will start with a couple of power cords.
Any recommendation on this??