i won't worry too much about card speed. i don't really think any of the pentax dslrs would be limited by card speed. it is usually the other way around. of course i could be wrong.
that said, having a faster card makes it less painful when you transfer files between sd card and computer. ultra ii is not the fastest right now, but it is good enough for me.
IMHO, K10D maximum burst rate is 3, doesn't take much advantage on Hi Speed memory card during shooting.
Using Pentax cannot burst like mad as using other brand DSLR.:bsmilie: