Jaskot, the VWC quote and mention of the Mark Rippetoe article on cardio do warrant serious discussion, IMHO. I don't know if that's what you wanted in this thread, but I'll offer brief reply:
Strength training is the most productive use of my time. I'd be all for having better strength-endurance if I didn't have anything else to do all day. Strength and mobility training make everything about the rest of my life better: I sit straighter, I walk better, my body composition improves - all things that matter to me because they make the rest of my life better.
In other words, much as I'd like to be in ideal condition for a Viking or other attack, I'm not - but I'm very, very happy with the condition I'm in. I typically do exactly 1 set of kettlebell swings most days at the end of my strength workouts. Lately, it's been 1 set of 1-arm, 28 kg swings. I did 10L+10R in about 30 seconds two days ago. (I take the weekends off.) The law of diminishing returns applies here - doing 2 sets isn't going to double my strength-endurance so I stick with a single set or some other protocol that keeps me in the 30-seconds to 2 minute range - that's enough for me, especially when done at the end of a strength workout.
Of course, your mileage may vary, and if strength-endurance training works for you, then by all means, go for it, and do a few swings or snatches for me while you're at it.
-S-