The nik filters were a great purchase. I really enjoy them. The ones I use the most are midnight, brilliance and warmth, and monday morning. You can find more info here.
http://www.nikmultimedia.com/welcome...alOffers.shtml
I haven't found anything like Lucis and I really like what it does, but I'm not as convinced of the value of this filter--yet. :-)
http://www.lucisart.com/
A big part of the effect is just from putting lots of different pattern fill layers in soft light blending mode over the image.