Probably the best sound per dollar I'm aware of would be the Axiom speakers that are really getting some nice press and reviews from owners. Given what I've read they would seem to be at another level over the NHTs, and I'd forget the Gallos if you at all care about sound. They make several models of small speakers, but I'd recommend the M3ti that I think is about the same size as the NHT Super Ones(although they make at least two smaller models that might work better given your constraints) and sell for around $225/pr. In the U.S. they're only available through the website(it's a Canadian company), which is www.axiomaudio.com, and they offer a 30-day money-back guarantee. You can read reviews on Soundstage.com and more if you search in ecoustic.com. Best of luck.
Tim
Tim