Originally Posted by Matthew Allen 
Don't dismiss zooms outright, dismiss bad zooms. Don't forget that the majority of modern photojournalism (and wedding photography) is done with zooms - good ones are capable of producing outstanding images. That said, the Pentax system's most interesting lenses are its primes - Pentax is one of the only manufacturers doing anything interesting with their fixed-focal length lenses and the Limiteds are just lovely.
It's heresy to say it here, but I think as a commited Pentax shooter I have a right: Pentax would not be my first choice for wedding photography. Given a sufficiently large budget, I think the ideal wedding system would be based around 2 or 3 Nikon D3s. The D3 has the best combination of low light capability and all-out performance on the market - combine usable ISO 6400 with an f2.8 VR zoom and you have a formidable and highly versatile setup.
Matthew
Thanks Matthew for the Nikon Advice, but I want to stick to Pentax, even though I own a Canon EOS, which is film based. I decided not to go with pop brands, as I dont want to pay little more, for a little extra brand value. D3 is expensive I feel, Even though I understand the fact that, choices of lens becomes better with these 2 bigger brands, but.. I want to take some calculated chances with Pentax. ( I guess it would be fun to overcome some limitations of Pentax, if any, by trying to be inovative and learn few tricks here and there..)
In short I find it painful to start the entire exercise of thinking about another brand except Pentax.
Thanks,
Dips