My commute is 37km each way - close enough to 25 miles as not to matter.
I'm not doing it as often as I should, primarily due to client meetings that are all over heck's half acre and it's just easier to deal with them when not on the bike.
I ride eastward in the morning and it takes about 1:35 - riding westward on the way home takes more like 2:10. On days when I'm biking in, I rotate my day earlier (I'm normally a 10-6 kinda guy) so that I'm leaving the office by 4pm or so.
I agree with above poster about how cranky I get when I haven't ridden lately. It's been more than a week and I'm all twitchy... it just didn't work out today. If I don't ride tomorrow, I don't want to be near me.
As for the health benefits of the long ride... well... in less than a year, I've gone from a 44" waist to a 36" waist... this morning I forgot a belt on my 38" jeans and I'm looking really fashionable with the low-slung-falling-off-my-hips-even jeans that I only dreamed of wearing when I started this, let alone the fact that I need to buy new everything several sizes smaller than all the clothes I got for xmas.
I wouldn't change a thing about my commute.
Oh, but be sure you've got a safe place to leave your bike overnight and an alternative way home (I use public transit) for those days when you cannot face the idea of more than 2 hours into a strong headwind after a crappy day at work. Some weeks I've only gone one direction per day and supplimented with public transit.