Wow, outstanding responses, thanks everyone! This has been hugely helpful. The Salks weren't even on my radar, but after reading all of the reviews (thanks Swerd) I'm quite interested. Is there any way to audition it before buying or should I just do it?
With a Denon AVR4310, Salk SongTowers, SongCenter, NHT Superzero 2.0, and keeping my sub (which is actually quite good), we're looking at ~$3200. Throw in cables and stands for the center/surrounds and we're probably near $3600. Might use the budget headroom for some of the amazing woodworking upgrades on the Salks; some of those photos are stunning, especially the one-piece baffle with the burled veneer.
From what's been suggested, it sounds like the recommended equipment is an exceptional value. Equipment-wise, what would I gain by using the rest of the budget? For example, I'd had my eye on the Marantz SR7005 ($1600) receiver; is it worth the extra $600 over the Denon? Should I get the SongSurrounds over the NHT SuperZeros? Slerch suggested the B&W's (presumably the CM series, maybe a pair of CM8s + CM Center), which would get me near that level. Is that a worthwhile investment or should I just pocket the difference between the recommendation and the budget, which I'm happy to do?
Thanks again for the help, your responses have been revelatory for a n00b like me!