Since buying the 550D I’ve had many people suggest a 50mm lens to me, usually the 50mm f1.8. Convinced by the sheer volume of advice more than anything, I went ahead and treated myself!
There’s no doubt this will be a fantastic portrait lens, but I’m not convinced it will be such a great match for my style. I appreciate the shallow depth of field, but the details are a bit too soft for my tastes. Nonetheless, the pictures have a lovely quality. I may have better luck with higher f numbers.
halfblog.net 
Don’t you just love this lens? I wrote about it some time ago on my blog, a few people seem to agree: http://www.dzierza.com/2010/03/my-nifty-fifty/
I remember reading this! Unfortunately new 50mm lens for Pentax are much more expensive that Nikon/Canon.Glad you are enjoying this:)