SSD is supposed to be better because there's no vibration or tracking error to deal with. Then again, it's all 1s and 0s, so you'd have to be fairly picky to notice any difference. And there's the cost, especially - astronomical for a drive capable of storing a decent collection. I HAVE toyed with the idea of getting a smallish SSD that would act as a swap drive for whatever's playing, but not sure exactly how you'd implement that in JRiver ...
There's an interesting series of articles in Absolute Sound dealing with HTPC tweaks, but you're talking some serious tweaks like $1000 power cords and such. I'd have a hard time enjoying music knowing the kids are going hungry because of a power cord. You can find some decent looking stuff on eBay for around $50-70US that might be in my budget.
For room correction - not sure why it would have to integrate with JRiver ... I use TrueRTA, and it's pretty much a one shot deal unless you do something to change the room acoustics. I run it from a laptop with a calibrated mike, then just transfer the resulting curve to my equalizers.
PS ... I understand about the best bang for the buck using an outboard DAC is going with the shortest possible usb cable. Rumor has it that even a cheepo one footer will outperform an audiophile grade three footer. Don't know myself - I'm real happy with an E-MU expansion card.
Also considering adding an asynchronous timer to the setup. Something like the Musical Fidelity V-Link. It just plugs in between the computer output and your DAC and basically replaces the onboard clock. Simple version as I understand it - the OS generates audio in blocks of data jumbled up with all the other stuff that's happening at the time. The asynchronous timer's job is to sequence all the little blocks of audio data correctly before hitting the DAC, and it also sets the audio stream as top priority on the computer's to-do list, eliminating a lot of processing delay and potential hiccups. Supposed to be a major improvement in sound quality and very reasonably priced if it's half as good as I've heard.
Obviously, if you're running an Ayre QB 9, cost is no object, so hey, get one of everything. <G>