First "audiophile" system, now what? Suggestions for best "bang for the buck" upgrade?

Lots of experienced advice here.  I don't know where you live, but if you are in a metropolitan area where AC quality is questionable, then a cost-effective power filter/conditioner might make the greatest difference .  In the end, the sound our stereo produce is a direct product of the AC coming to you from your power company.  The more distortion/hash on the incoming AC line, the poorer the performance of your other components.

For the record, it looks to me like you've made sound system decisions so far.  Clean power will allow your entire system to shine!

With your current equipment and if you have good ears you should easily be able to hear differences in cables now. It is not necessary to have ultra-high end gear to hear cabling changes. My systems when I first delved into cables about 30 years ago were by no means high end, and yet in every one cables were obviously noticeable. This is to encourage you that you do not need to put off that decision, if you wish, due to perception that your gear needs to be much higher performance. It is wrong to presume that one needs to have much higher performance gear to hear the effects of cable swapping. 

Thanks for the compliment, I needed that. I put together this system over the last 6 months and the whole proces has been wrought with anxiety and second guessing. I don't have the luxury of a brick and motor store to listen and compare equipment, so all of my ideas came from looking at what was listed on Audiogon, then reading reviews, which then mention other equipment, so maybe something else is good, so read about that, then read a conflicting review, then try to read between the lines. Hours and hours and hours of late night research (I'm guessing most here can relate to), then finally having the guts to make a buy and hoping when it arrives that you get what you thought you were getting. 

I do know that my records and CDs (and FLAC files) sound very, very good. Well mastered vinyl sounds as good or better than digital files on this setup, and it all sounds really, really good and looks cool (which is part of the equation for me). So I'm happy......but what about a better needle?.....then better speakers?.....then better tuntable?...then power supply, then cables, and DAC?... Once its is sounding as good as I've got right now, then the rest will be just more fun. And money.

Thanks for all the good advice.

Etwilley,

Loved reading your post above.  You're right.  The vast majority of us who care enough about audiophilia have walked the same road that you are now on.  You did the research, you took that absorbing path leading to a purchase.  As good as your system sounds now, and I have no doubt of its musicality, if you are like most of us, you WILL walk farther down the road as your listening experiences reveal how much better it can get.  I speak from recent experience after making my first speaker purchase in 22 years.  Until I experienced my new transducers with my system I never would have known how good it can get.  I WAS satisfied with my other speakers for all of those years until these babies burned in.  I hope you get to have such moments of aural surprise as you continue to realize what's possible.  Enjoy the journey!

There's never enough money is there.
So if you want amazing speaker cables on the cheap you could try what I did. I had a whole lot of used Cat5 cable (saw a good review of measured outputs of various cables) get six Cat5 cables for each speaker 25% longer than your needs. Twist two together x3. Then braid those three twisted pair. The real diy fun is separating the dark from light at both ends, striping, and attaching banana plugs. Be sure to purchase a continuity tester ($15) to make sure a stray wire didn't cross over (do this before you attach banana plugs) plus it's an amazing work out in your wrists. You'll look like Popeye when you're done. 
I am also impressed that there are a lot of guys out there keeping the cost down on amazing equipment like Sandy Gross with his Goldenear speakers. I also wanted the most bang for the buck for cheap. 
PrimaLuna Prologic integrated tube amp, Sony HapS1, and Goldenear Triton Ones, my homemade cables, power conditioner, and good power cords. The variations and recommendations are endless so enjoy YOUR journey.