My last trip taught me that what I'm missing in collection of lenses is a more general traveling lens. Carrying all those different lenses around was just too bulky and I ended up pretty much keeping the EF 28-105mm on all the time. However, because of the type of shots I was taking, the 105mm didn't have the range that I really wanted. This X-mas I finally decided to go for my first L-series lens to address the short coming of my collection.
I decided to go with the 70-200mm f/4L IS lens for a number of reasons. The reviews (and here) on the quality of this lens is superb and even though it doesn't have the f/2.8 of its renowned older sibling this is a much less bulky lens and 1/3 the price. I think the trade-off is worth it for amateur photographer like myself especially since I want to be able to carry this lens around when I'm on vacation.
I decided to go with the IS version even though it's a hefty premium over the non-IS version but I'd much rather invest in a lens then get photos that causes me to kick myself later. With this lens, I figure that my travel collection would be 1 prime (either the 28mm or the 50mm) and/or the 28-105mm and this one. Most likely I will try to stay with just 2 lens to keep the weight down.
I haven't had a chance to put it through its paces, but maybe the upcoming holiday will give me that chance!