The glass is one of the main reasons I chose Pentax when I decided to by a Digital SLR camera. The latest Pentax cameras accept all lenses made by Pentax, albeit with an adapter for M42 screw mount threads.
The first two images were take with a Pentax-M 28/3.5 whilst the second pair were taken with the Pentax-M 35/2.0. Both of the lenses still produce excellent results and cost me under $50.00 for the two.
Remember, before buying a camera body check out the range and price of lenses. Can you get the lenses you need and the lenses you want at a price you can afford.