I need to get rid of my JBL 4311s don't I?

I have a pretty decent system and can't help thinking that my 70's JBL 4311's from a radio station are holding me back.
I have them perched on some leadshot filled Target stands...toed in about eighteen inches from the wall. To my ears they sound great if the vinyl I am spinning is great. They seem to be a very revealing, flat, near field monitors. What speakers should I be checking out as replacements? I have an ARC Ref1, VPI TNT 3.5, ARC Ref Phono, ARC D130, old Cardas Hexlink interconnects. My local hifi emporium has a pair of used Quad EL63's that they are asking fifteen hundred bucks for...I listen mostly to jazz...lots of mono....and soul from the 60s...any suggestions? I am not concerned about cost but do like to get some bang for my buck. I have considered going all out for Wilson's, Revel, or B&W but really don't know where to begin. My next purchase is certain to be some kind of monoblock tube amplification but I guess that is for another thread. Thanks in advance for your suggestions!