your profile shows that you have the kit 18-55 and the FA 50 1.4
If you are looking for one lens to leave on your camera, all the time, you will have to compromise aperture, range, or cost. Probably two of the three.
Suggest you go the
Lens Review section of this website and look at what is available from Pentax and third party manufacturers.
A way to decide what you can live with on the wide end is to use your 18-55 at 18, 24, 28, 35 mm to see if that is wide enough for the shots you enjoy taking.
The
28-200 is certainly an option, and you could always use the 18-55 for wider shots.
Sigma and Tamron made 18-125, 18-200, and 18-250 lenses over the last several years that might allow you to sell the 18-55 as well and go with one lens most of the time, saving the 50mm 1.4 for low light and portraits.