ok a pair of 5200s represents a significant investment on my part. I guess I'm unlikely to see them on the s/h market yet. So lets talk about D5ks... aside from the aesthetic disadvantage (the 5200s look really good!), what are we talking about in terms of performance between 5ks and 5200s?
I agree with VK - significant performance differences (5200 vs 5K); Although I would caution against getting caught up in the upgrade-itous disease. Instead compare how a given purchase will change your existing situation relative to your available budget. The 5Ks are wonderful DSPs with a great sound for smaller rooms and can be had on the used market fairly regularly (from those disease infected).
I personally like the straight line look of the 5Ks - They also have a very neutral tonal quality (to my ears) - which means if you later upgrade to something else, the 5K rears will likely work for most any new DSP fronts you may get.
If you can (or choose to) afford the 5200s, go for it; But if not, the 5Ks (get the 24/96) are a great $ value / DSP sound today IMO...
ken