What a great room you have... enjoy the journey. Don't be afraid of used equipment... you'll save a lot on the budget.
As for type... I'm partial to..
Vandersteen 3aSig. $2k used
Theta Dreadnaught 1 or 2 with 4 amps... $2k used
Preamp... Audio Research, VTL, Pass... you can pick up a great sounding preamp for $3k > $5k
Source... ??? your choice. Streaming.. CD... Vinyl so many choices from $1k to ???
Cables... up to you. I would start with used AQ or your favorite brand $1k for entire system. They can make a difference... this is only an opinion.