I am so conflicted. I have a trip to Italy - like a lifetime trip - in 2 months. I bought a Pentax K-5 with an 18-135mm lens as an all around. Will be in Venice, Bologna, Siena, Lucca, and Rome - is that lens sufficient or should I get a super wide ? I will have to hide the purchase from my husbandino because he's already having heart palpatations from how much I spent on the camera. He says - don't bring it- ... just buy post cards - so that's where he's at. I really think a 10-20 or 12-24mm would be so great and I so get that life is short - so should I sneak one into my kit (I've got plans for that process) or is the one lens I have good and avoid the expense and hassle of lens changing ???? HELP I go back and forth. Opinions everyone (I know there should be plenty).

You know that it's really sad that your spouse will not support you in your photographic endeavors.
Here you are taking a once in a life time trip and your husband is being in my oppinion just a little bit selfish. This trip costs XXXX amount of dollars and you want to take home as many memories as possible.
Just think years from now all you will have to remind you are those memories and now digital images.
But I digress! I feel that you have several lens choices. Staying with Pentax Brand lenses a 55-300 f 4.0 - 5.8 ED at $429.95, or a 50 -200 F 4.5 - 5.6 EDWR lens at $249.95 are for starters good choices. I think a short telephoto lens will allow for more shots ,therefore more overall use than than say a 12 - 24 mm lens.
Not that a 12- 24 or a10 -20 mm lens would be a bad choice. it's just a little bit more expensive.
Remember this! You are building a system one lens at a time. Artists have so many different paint brushes. The reason is because each one is designed with a spefic task in mind.
My opinion only! If possible go to a camera store and see what each of these lenses are capable of, by mounting them on your camera and taking a couple of images with each one. (remember to keep a memory card in your camera body.
If you can not do this, I suggest that you grab several travel magazines by going to your local book store or library and determine a shooting itinerary for yourself. Write down all the places that you will be visiting and keep careful notes of which lens you would want to use.
When you are done deciding which lenses you want to use ,add up all your colunms.
Your answer is now right in front of you! It's the one lens with the most check marks beside it!
Keep this in mind an 18 -135 mm lens is a great walk about .
Generally an 18 mm at the wide end should suffice.,however there may be times when you want to get closer but are unable to do so for one reason or another. Now comes the beauty of a longer telephoto lens.
Here is an example. You want to photograph a really beautiful building but right next to it there is lets say a run down slum . What to do? No worries! With a telephoto lens you can zoom in and isolate your subject matter from any clutter. try that with a wide angle? On the other hand wide angle lenses will allow you to take in beautiful shots that are just teaming with robust activity.
Again I think that you already own one with the 18 - 135 zoom lens.
In closing try this after determining what type of shots that you think you will be taking walk around your city or town and try and duplicate those photographs . This will give you another idea of what you need in terms of a second lens!
I certainly hope that this advise will help? :thumbup: