Originally posted by jatrax K-3 or K-3II and the DA 16-85 will be a very good starter kit that should leave you some cash for additional lenses. Add the Pentax 12-24 if you really need ultra wide.
A k-5IIs would save you some money over the K-3 series if budget is tight.
jatrax is on the money. The DA 16-85 will blow you away given your current reference point, and gives you a decent amount of width (fov so 16mm on APSC is about 24mm on your film camera). The image quality, across the entire frame, is stunning, add on WR and the DC autofocus and you have a great walk around lens. The DA 18-135 is also a strong contender, a little smaller and lighter, some more reach at the tele end, but you do lose 2mm at the wide end (and that isn't insignificant if you like wide) and the edge performance isn't as strong.
Team either up with a current Pentax body and you will be amazed. K-50 is a good price, with the 16-85mm you end up around $800 @ B&H. With the K-S2 it is near $1000, and the K-3 puts you on the edge of the budget danger zone, but if you want top quality shots you might be able to justify it. You can get the K-3 with the 18-135mm for just under $1000; really good value if you think the 18-135mm is the lens to go for.