My long runs have generally been 10 or so miles, but the past month and a half or so, I've been extending them a bit, sometimes to close to a half marathon distance. I've also been working on going deliberately slowly, as I've run myself into a plateau in the past when I've run all of my runs at a similar pace.
Not surprisingly, the combination of going for a longer distance and going slowly adds up to taking a long time to finish these long runs. Today's run was 12.14 miles and took just under two hours (1:57:12, to be exact), with a total elevation gain of 1534 feet. Now, on a treadmill without the hills in my neighborhood, I'd probably have run at more of an 8:35 pace, but even that would've taken me more than an hour and 45 minutes to finish 12 miles.
Endurance-wise I feel pretty confident that I could've gone at least another three miles, but as awesome as running is, that's really getting to be a ridiculously large part of the day.