[hks_kansei]

My kit usually has the following for a day out:

Pentax ME
Pentax *istDS
Sigma 18-50
Pentax-A 50mm F1.7
Pentax-A 28mm F2.8
Pentax-A 70-210mm F4 (if I know I'll need some length)

[Kameko]

I like to keep it light and simple. I'll pick one lens for the week as my "go everywhere" lens and only use that. If I'm out specifically birding or exploring abandonments, I'll bring my wide angle and telephoto as well. Most often it's the 31. If I were in your shoes, I'd throw the 35 on there, have fun and not worry about what lens to use for this shot, that shot or the other.

[reeftool]

The older I get, the lighter my bag gets. On hiking trips, it's a DA 15 Limited, DA 40 Limited, DA 18-55 and sometimes my 55/1.8 Super Tak with extension tubes. I will on occasion bring a telephoto if I think there is a probability I will use it. I usually don't use it. My DA 10-17 is along sometimes. I can carry my camera hanging from my Cotton Carrier vest with the kit lens and keep 15,40, and 55 with a tube in my jacket pocket. I have recently purchased a Sigma 17-70 which has a macro range and it will replace the 18-55 as a walk around. It's bigger and a little heavier but the range will work very well for my needs. I carried an F 35-70 for a while but it's no longer working.

[mtux]

I'll take a different tac: join the "single in" challenge and shoot with one lens everyday for a month. Repeat until all of your lenses have had their month. What this exercise teaches you is what you really wish you had that you don't have. It will provide a personal framework for what YOU need to fill out YOUR kit.

+1 to the Single In challenge.
What I'm having in my bag since I joined the "Single in" challenge is my Camera and current month's lens only! so I have to learn that lens and that focal length. I've learned a lot since then.
Well, Whenever that I think there might be a chance of a shot which e.g. needs a wide lens and my lens is a long one, I will carry another lens too.

[tele_pathic]

Why not bag a decent fisheye lens

I see what you did there....

[Kerrowdown]

What would you carry?

Get one of these wheeled camera bags, problem sorted you can then take the lot.

[Treedo]

I've enjoyed reading the suggestions. Thanks to all who replied. I've decided I need 3 more lenses to have the complete kit for me (for now). I will be looking for a wide angle lens (10-17mm), a fast 50, and most likely the sigma 50-500mm. Going to be an expensive year!

Chris

[EarlVonTapia]

One thing that hasn't been touched upon is what ELSE you should carry in your bag.

I always have the following things in my bag:

Spare battery (K30)
Spare battery (Q)
Spare memory card
Mini Rocket Blower
Lenspen
Microfiber cloth
Ultrapod II

I will be looking for a wide angle lens (10-17mm)

May I suggest the DA 10-17mm Fisheye?

The reason is because it doubles as a normal ultra-wide and a fisheye lens.

@ 17mm the field of view is almost the same as a Sigma 10-20mm is.

Lightroom makes transitioning from a fisheye to a normal picture as easy as 1 click.

And of course you can go wider than that if you need to, and you can take fisheye shots.

The picture quality is the same between the Sigma 10-20 and the DA 10-17 (I have owned the former, currently own the latter). The fisheye is cheaper, smaller, and lighter. For casual work this is a no-brainer in my opinion.

Here's a throwaway shot.

First shot is at 17mm, not de-fished.

Second shot is de-fished.

That blurring in the edges? You will get that with a 10mm normal lens anyways.