Possible bookshelf upgrade


Hello to all.
Here is my question. In my bedroom I have as my mains a pair of Definitive Technology Studio 55. I am thinking of upgrading. I run these with a Marantz SR5010.One candidate is the Paradigm 15b. So, would I be gaining much doing this? They are in a 5.1 system. My budget is up to $2000. I have heard the Nola boxer, which is very nice. I am just not sure if at this range it would be significantly better. Thankx in advance for all advice.

arthurd
I'd look at Focal 906's.  Truly amazing if you can get them set up right in the room.  

The paradigms are great too, but I'd rate the Focal a notch higher.

I'd also be sure to listen to Ryan and Scansonic as well -- but at the $1,500 price point, the 906 Focal is just unfairly good.
Well, if I am not mistaken, the DF 55s sell for ~$500. So with a $2000 budget you can most certainly get an improvement. 

Do you use this system for 2 channel music listening as well as for 5.1 movies? To me the value of the upgrade would depend on this.
Yes, it is part of a 5.1 system. I am also changing my primary listening  area as well. I have questions about that. . Not sure where to post that as I have questions about speakers and electronics.
Perhaps a pair of Zu Omen Bookshelf? I own them for my office and they are quite nice. Also, less than $2k.
Bob