In reply to Paul Evans:
Somehow I seem to have ended up with quite a range of lenses. In no particular order
DA 35 2.4 - Brilliant cheap lens, sharp and fast, on my K7 most of the time.
DA 55-300 - A good zoom, pretty sharp.
F 70-210 - Second hand bargain, sharp and good colours. Auto-focus isn't amazing, keep thinking I should sell it, but am also aware the price will shoot up if the FF Pentax ever arrives.
DA 18-55 WR - Came with the camera, good kit lens, mainly gets used if it's raining.
M 50 1.7 Nice and sharp, bit of a faff to use on a digital body, rarely used since I got the 35.
M 28 2.8 Good lens, but don't think I've ever used it with the digital body (bought when I was using an MX)
M 75-150 A ridiculously underpriced lens, albeit one I never use now I have the zoom range covered with AF lenses.
I also have a Sigma 10-20 which can be great for climbing photos, really like it.