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


After being beguiled with mp3s and the TV AVR, I finally realized I missed having a dedicated stereo system. With a budget of $2400, here is what I put together:
  ProJect Carbon 1 w/TizoAcrylic platter and Ortofon Red cartridge,
  Hagerman Bugle2 preamp,
  Vincent V-60 tube amp,
  Martin Logan 12 speakers.
 No special wires or cables. My room is 14x19 that is open to the kitchen. Compared to what I had been hearing, this system sounds fabulous. But now I want more fabulous. So I am writing to seek help on making short term/long term plans to upgrade. Short term means the biggest improvement in sound that costs $500 or less. The long term plan could cost maybe $2-3k or more. I have read that going from Ortofon Red to Blue might be a an inexpensive but very noticeable improvement? If speakers are my weak link, then maybe Martin Logan electrostatics would be good (when my ship comes in)?
I welcome any suggestions.
128x128etwilley
You are receiving a lot of sage advice so far. I beg to differ on a couple of points. One being cables/power etc. While this can certainly enhance (and protect) your system, your question was "bang for the buck". In my experience, cables, power cords etc. yielded subtle (if any) improvements in sound. BTW, different isn't always better. Again, in the "bang for the buck" category, look to your speakers. That's where you will reap the greatest rewards for your $$.
Install a dedicated line before anything else. Not expensive and you could even DIY - I did. 

In my experience, cables, power cords etc. yielded subtle (if any) improvements in sound. 

Which did you try?
A quick story about speaker cable. I'm going be memory but here goes, at an audio convention a dealer was demoing a McIntosh system, I do not remember the configuration exactly. Listeners were remarking on the exquisite sound with the typical "transparency, inner detail, micro dynamics" etc. comments. The gent who had the display quietly laughed to himself as his speakers cables were modified Belden extension cords...This is not to be a diss on exotic cables, just relating a real world story...