An M50/1.7 is a no brainer, but beyond that you're going to need to be more specific about what you think you need. If general street stuff a zoom is a good way to go until you establish your shooting style and preferred focal length. For this the kit lens is fine, but

1) The Tamron 17-50mm is a bargain with near-stellar IQ (costs 250 quid or thereabouts s/h - if that sounds a lot, compare to the DA16-50mm!), or...

2) An F35-70mm would be a low-cost (35 quid?) 'pocket-sized' addition to your kit (and a decent range for 'street shooting with excellent IQ).

If you are looking for alternatives to the rather expensive 16-50mm, check out Pentax Forum's comparitive review (go to the main site and click on 'In Depth Reviews').

ped·ant
n.
1. One who pays undue attention to book learning and formal rules.
2. One who exhibits one's learning or scholarship ostentatiously.
3. Obsolete A schoolmaster

kill·joy
n.
One who spoils the enthusiasm or fun of others.

I didn't think the Kx had any sort of mic input whatsoever!

You'd be better off recording the sound remotely and lining up the audio track in editing. I don't think WMM has any neat way of automatically lining up the audio and video tracks, but it's certainly possible to get it close enough - select the audio track and use the arrow keys to nudge it one way or the other!

Recording the sound remotely will also allow you to take the audio track all in one go, and will free you up to shoot some cutaways to add interest and also cover over any cock-ups in the filming

Tbh I think using WMM, while possible, will drive you nuts and I would advise you to obtain a more full featured program by any means possible

The plastic canisters are sealed, so I wouldn't worry.

The specs haven't been confirmed yet... the road map is subject to change as it clearly states! Pentax reps have confirmed it is undecided whether to designate it a DA*. The mock-up recently unveiled does show weather sealing around the mount at least, but that could mean 'WR' designation which would be more in line with an attempt at an affordable super-tele.

Perhaps they are simply busy enough that they focus on the jobs that are more profitable, or fit with the studio 'ethos; they are trying to develop? I guess it's their business and they can decide what terms they operate on!

After resizing for the web, always sharpen!

Wow, will the K5 not even manage to autofocus on a stationary passenger jet?

I jest - probably just needs a 'post-resize sharpen'....