[J_Gasper]all of those were shot with the 50mm?
Not all of them, I think the two of the guys in the market were shot with a 28 and the one of the chapel at Versailles, as well as the flag under L'arc De Triomphe. Everything else though, yes.
I was using my Olympus OM-1, all that it shot on film. As you can see, a couple are a little soft because I fucked up. If you have a prism that helps you focus in your camera, it's not as big a deal, but if you just have a matte screen on a DSLR finding focus might get annoying - depends on how good you are with it.
Here's my advice - don't worry about what lenses you would take to make sure you get the shot 100 percent of the time. Take the lenses, or a lens, that you will ENJOY shooting. You'll only lift your camera to make photos that you really think will be worth it, and you'll enjoy doing it - thus enjoy your trip more and live more in the experience rather than fiddling with your camera.
Although, that could be terrible advice if you're the type of person that really really hates it when you don't have the right lens for just the right situation. I let go of that side of my self on vacation, and I'm pretty good at it - some people aren't!
BTW - super jealous that you are going to Portugal. How long and what's your itinerary?