Just made 3 days solid of going bike commute from my new digs in NorCal.
17 miles each way - that's a lot farther than I've ever bike commuted before, and long enough to actually count as a workout for me, especially since I can hammer it the whole way since I've got a bike lane the ENTIRE way (gotta love NorCal!)
Unfortunately, I was perhaps the only commuting cyclist out there on a big stretch of bike-friendly road. I passed a handful of recreational cyclists , but likely no commuters. A shame, given the awesome weather.
Lights also kill your overall speed. I ended up averaging only 18mph for the entire route, despite going 22+ for most of my moving ride time on the flat stuff (most of the way).
If it weren't for the logistics of time (I have to work from 7:30AM to 6:30PM, full time) , I'd do it 5x per week, but I'm so time crunched that I can't do it 5 days per week. Probably 3x/wk is all I can do.
I've been doing it on a pure road bike (Giant Defy 3) and carrying a small camelbak. Surprisingly, despite generating tons of sweat on the ride in, I'm fine for the day, even in suit and tie after a quick wipedown in the bathroom. I think the key is to shower before getting on the bike (weird, I know) and to have clean, fresh riding clothes. Particularly socks, if you risk the chance of stanking up the office!