So I my commuter is a Surly Karate Monkey, one of the most versatile frames out there.
I stole parts off my old (13 years old) Ice Bike after a convoluted series of events designed to get me a 29er Mountain Bike. That's another story that did end in 29er but not the Monkey which, as I said, is my commuter (though I have snuck the Monkey onto some single track a time or two...). The goal with the Monkey was to just get it working and then shop for parts to upgrade it as I found the right deals.
I came out after work the other day to where my current employer has the corporate bike rack. I'm lobbying for an upgrade but not holding my breath, contractors rarely get much of a voice in such things but I still figure it's worth trying. I would guess there are several thousand folks in the building and the security dude said lots of folks ride in the summer. Of course six (count the spots in the rack) might seem like lots to him. At my last job there were more than that when it was below zero and closer to a hundred in the summer but that was downtown, not in the suburban setting I am now in.
Then I notice something's missing...Damn, I think, it's gonna be a long ride home at slow speed since I am down to one brake. Fortunately, the remaining brake is the rear; if it had only been the front, I may have opted for another way home since it was a very snowy, icy day and I had already gone down that morning in the snow. So it turns out the brake had popped off right there and was laying on the ground. I figure it must have happened as I jury-rigged the bike into locking position (how the hell are you supposed to lock both wheels and the frame on THAT bike rack anyway?!)
Well, sometimes the bike gets to decide when it's time for an upgrade and since disc brakes were on the list of upgrades to be done, I followed it's lead and now the Monkey is sporting these. What a cool deal to have a frame that can support both rim and disc brakes!
Now it's time to think about a drive train upgrade. That 29er Mountain Bike I referred to has a nine speed cassette and it would be sweet to have the option of swapping wheels so I could choose studs or not without a tire change.