The KEF speakers are darn good.
I've owned the KEF X300a for a year, and have been nothing but impressed with how good they sound.
But if I was to upgrade, I wouldn't hesitate to pick up the LS50.
Also, the Audeo PFE012 just arrived. They impressed me straight out of the box. Best $35 I've spent. With the grey filters, they sound like a ER4S/CK-10 mix.