Which types of speakers are ideal against a wall?


I currently have rear ported floor standing speakers (Dali Euphonia MS-4) against the wall due to no other room options.  Are these speakers feasible?   I also have 2 Rel 528s along side each speaker.  I am looking at replacing the speakers.  I also have 2” acoustic treatment w 2” brackets behind the speakers.  Any speaker suggestions in the the 5-7k range (used) welcomed.  

Equipment:
Modwright 150 SE 
Dali MS-4
Rel 528 Qty 2

Room 15 w open wall  and 17 L 
puffbojie
The subs need to go against the back wall too.  Any idea if they would be more effective lined inside the speakers or outside the speakers?
I had the Wilson Audio Duette 2's and they had to go against the wall.  They were outstanding.  Sometimes, you can get a great deal on used but maybe still above your budget.  Raven Audio has just launched a new speaker line that you might want to investigate.  Celest Towers for under $5k.  Call James or Dave at Raven.  
Snell Type A's! Designed to be used that way! I have a pair (III's) from the original owner - bought from the Connecticut audio store where I once worked! Talk about serendipity! The Type A III's will KILL just about any of today's over-priced five-figure speakers! Peter Snell got it right!
If you don’t mind the size of the speakers, I also suggest Von Schweikert speakers VR22.  I love them but sold them since I didn’t have enough space for them.  You can place them against the wall.
If your decor dictates speaker placement, I would highly recommend digital signal processing.