As stated start with a pair and save for a nice subwoofer
The JBL Studio 530 have been preferred over some more popular and expensive
speakers - and they do have some good bass.
A list (subjective) of some speakers, that the testers/owners chose the Studio 530 over are,
Aperion Intimus 5B, Ascend Acoustics Sierra, Audioengine P4, Axiom Audio M22, B&W 683 & 685,
Dali Mentor & Icon, Dynaudio Contour & Focus, Epos Epic 1, GoldenEar Triton & Aon, Linn,
NHT Classic 3, Magnepan MMG & 1.6, Monitor Audio Silver RS6 & RX1, RSL CG4, Revel F12,
Tekton Design Model 4.5, Klipcsh Reference, PSB Image speakers, Totem Rainmakers, Totem Mites, Triangle Comets, and Vienna Acoustics Hydens.
http://www.amazon.com/JBL-Studio-530-5-25-Inch-Bookshelf/dp/B00622STI0/ref=sr_1_1?ie=UTF8&qid=1436395980&sr=8-1&keywords=Jbl+studio+530
Lower in level - however still would be nice for the price
The Studio 230
http://www.amazon.com/JBL-Studio-230-Bookshelf-Loudspeaker/dp/B00GJXSWZW/ref=sr_1_1?ie=UTF8&qid=1436395996&sr=8-1&keywords=Jbl+studio+230
I would easily choose these over the Polks you listed