Ken,
You have very nice equipment as is. I would stick with the Arials, unless you want to swap out all your speakers for a different brand. You could go to a 6 or 7 channel system if you have the room for it.
In general home theater sound distribution is:
50% center channel
40% L/R channels
10% Surround
You might get more improvment/$$$ in your system by working with acoustics at this point.
You have very nice equipment as is. I would stick with the Arials, unless you want to swap out all your speakers for a different brand. You could go to a 6 or 7 channel system if you have the room for it.
In general home theater sound distribution is:
50% center channel
40% L/R channels
10% Surround
You might get more improvment/$$$ in your system by working with acoustics at this point.