A few thoughts...
Chuck the old speakers, as mentioned the surrounds are a source of trouble, the crossovers most likely are out of spec with old caps etc and the speaker wire connections out of date. A lot of progress has been made in the speaker arts. Also using speakers in a critical listening environment vs pleasing background music in an office will have a major impact on your selection.
Look into using "Pure Music" as the playback software. No comparison to itunes. It does use the iTunes library structure but will playback in hi res. up to 192...which can play an important part in your dac decision. You can also control the output of Pure Music thru a remote. I use a Musical Fidelity M1A dac on both win 7 and a Mac mini server and enjoy the sound.
Speakers...don't rush and TRY to listen with your ears before purchase.If this is a long term purchase try to listen in person.
As a side your ears are most likely better than your other half. Most men in the hobby have trained their ears for what they perceive as pleasing sound, women on average have better ears and 17-22 yr old women have the best ears.
If you intend to have two working copies then have a third on a new drive for the archive copy and don't keep the drive turned on or plugged in...
Happy Listening and enjoy the hobby together
Wally