first, given it is a basement system with a 9 ft ceiling, let me say that room treatments are really important - get the floor soft, deal with corner and side reflections, also ceiling reflections -- upgrading speakers with a sub optimal room is a big waste of money and effort
second, try a proac floorstander. they accentuate vocals in a brilliant manner - tektons, already recommended, are another good one to consider, but the tektons get to be back breakers in a hurry
i would also suggest some excellent large-ish stand mounts you might consider, buchardt s400/s300, harbeths, spendors - they honor midrange and voice brilliantly... then couple with a pair of rel subs... this combo will put all the best high buck floor standers to shame in your application
finally, suggest you ditch the class d amp get a sweet class a-b unit - many out there to choose from
good luck!