Responses from tbromgard

Length of speaker cable effect bass response?
I have an NAD int amp, Usher speakers and 30' run of bluejeanscable in biwire config. I have had the cables in my system for 4 months or so. 
Is a Sub worth the bother?
IMO-I believe a good sub would help, but not a cheap one. Your Epos are fast and detailed, and a crap sub will just smear the speed and detail of the Epos. I know, I have experiemented with an inexpensive sub and Usher speakers (fast and detailed)... 
What is more important source or preamp?
I agree with Ivor-source is most important. Take the extreme: $10k speakers with $50 source. The speakers will sound like crap b/c of crap source. $10k source with $50 speakers. At least your speakers will sound the best they are capable of sounding. 
which preamp to buy???
I used a 24k with outboard power supply with the 2004 amp and Apogee Centaur Minor speakers with very good results. I also used the PV5 as a pre amp in the same system. I actually preferred the sound of the PV5, but both pre amps were very good. A... 
Live vs home system???
According to TAS, the reference should be live unamplified music-which always seemed like a good reference to me. 
What is more important source or preamp?
which preamp to buy???
I enjoyed my time with the Aragon 24k. Thats in your price range and would look cool with your Aragon amp. If you like tube sound try a CJ PV5 or similar vintage. Good luck 
I need an amp, can any recommend?
I second McCormack amps-very musical. 
I owned kg4 before and liked them very much. They are very efficient, play loud, have good extended bass and easy to place. They look good too with real wood vener. However they are somewhat large and heavy so shipping might be expensive. 
Musical Speakers
Some used Usher X718 are very musical. Can be had for $600 to $750. 
Integrated Amp for Tyler Acoustic Linbrook Monitor
Those are good ss amps. Consider any McCormack amp-I have a dna.5 and its very musical, authoritative and in your budget Good luck 
Recommendation needed for Turntable
I have the Sota Comet with RB 301 arm and Ortofon cartridge and the sound is excellent. The combo goes for about 1500. 
Changing to bookshelf speakers. Recommendations?
I can whole heartedly recommend the Ushers. Easy to drive, great bass response for a small speaker, and beautiful highs. Add great looks and youve got a winner. Of course, all your choices are nice-Good luck. 
Building Second System...which cables in my budget
Bluejeanscables.com are very inexpensive and built well 
Bookshelf or Mini Monitor
Usher's entry level is nice sounding.