changing overall tone

What phono amp are you using? The rest of your system seems to be good products for the money. I would definitely agree that you should not be looking to wire to help make the system sound better. Audioquest is a respected brand.

Stringreen's headphone suggestion is an excellent thought. I like my system, but it's in a difficult room (you know, wife and kids involved).

A sub-$200 pair of headphones (eg Grado SR-80 or 125) can add a new dimension to a mid-fi system; I love my SR-80's.

On another note, don't those Dali's have the twin tweeter? I'm surprised you find them "neutral to dull sounding"; I more often read of them being accused of being too bright.

Goertz AG series speaker cable will definitely add more high end tilt.

Aren't these speakers supposed to go with a sub?

You may be missing the oompf of the bass and therefore it sounds lifeless.

you can do quite a bit to make your system sound more lively with interconnects/ac cords and power conditioners. Although the money you could potentially spend on those would more than easily pay for a new preamp or amplifier (or both). An upgrade in cables could likely expose potential weaknesses elsewhere as well (i.e. make things too bright/etchy with certain equipment), so be cognizant of that as well.