The DA*16-50 is very good, and the DA*50-135 is truly excellent. The Tamron 28-75/2.8 is also said to be quite good, as is the 17-50/2.8 (I never had either one. I went from the nice DA17-70/4 to the better DA* zooms, and have been happy with them).
Then there's the FA*28-70/2.8 or the not-quite-as-good f/2.8 Tokina.
One of the above should really do the job. But you may start to pick up some primes, and you'll be more than happy.
A couple of years ago, during the brief time between when I sold my K-x and my new K-5 arrived in the mail, I got to shoot on the Universal back-lot. I had only my "old" K200D, plus my better Pentax lenses. I thought "if only the K-5 had arrived earlier!" So I borrowed a 5D Mk II for the day (with a 16-35 and a 24-70) and used it alongside the Pentax. I really thought I'd prefer the Canon results, so I was a bit shocked to find I liked the 10MP Pentax shots better. It was mostly the lenses.
I don't think of buying Canon L glass as snobbery, it's just what you have to do to get good quality with Canon gear. The Canon 16-35 is certainly good, but it's not truly impressive (like the Sony Zeiss is). But it's still supposed to be better than the 17-40. Instead, for the same money, get a DA15, DA21 (or FA20 or FA*24) and FA31 (or DA35/2.4 to save $800). There are a few nice lenses missing from K-mount (like the Tokina 11-16), but I don't think glass will be your problem.
Actually, just an FA20-35/4 (which I used to have) and the very compact (fits in the bottom of your pocket) DA15 will do quite nicely. Then add a DA*50-135. As long as you get the 50-135, I know you won't hate me, no matter how the rest of it works out.
BTW, I have a K-5 IIs on order myself. I shot a huge invitational cross country meet (at my alma mater) today. I got nice results from my K-5 (and K200D) today using the FA135/2.8, DA*50-135/2.8, and FA*85/1.4. The hit-rate of good (in-focus) photos became better as the meet went on and I got more used to tracking the runners with the AF, especially on the FA135 (which I was very happy with). See the Highlights Gallery:
http://www.racetimephotos.com/XC/DanaHillsInvite2012