I don't know what Pentax market share is in the US, I'm sure it's pretty small. Here in France they do pretty well, mainly because the photographic press is much more empirical about camera/lens performance, relying almost entirely on lab measurements to assess camera performance, and the recent Pentax offerings have performed very well, especially the K-x and K-r. I haven't seen any reports on the K5 or D7000 other than the initial 'look promising' previews.
TBH I actually don't know anyone here who owns a Nikon. Canon, Sony and Pentax yes, but no Nikon. Take with a pinch of salt, I clearly live in a bubble
. Canon are number one here by a country mile.
I might just buy a TZ-10 or LX-5 while I wait for the DSLR dust to settle a little - I need a new compact.