The one pattern that has emerged in single speeding over the last decade is the need to have a bottle opener somewhere attached to the bicycle. When Surly realease the Jethro Tule I thought it was the last word in cool simplicity. Various bikes have had bottle opener everythings (eg, chain tugs, headtube re-enforcement) and the idea has clearly caught on.
As mentioned before Felt have a single speed with a similar tool. Now for those who are too cheap to buy the original and don’t want to buy an entire bike just to get the tool you can now get a cheaper alternative from Cell Bikes. Cell are putting out some interesting fixes and single speeds and are worth a look. I’ve never quite trusted the generic Cell branded bikes but when it comes to single speeds it’s hard to go too far wrong. Anyway, check out their Super B Single Speed Spanner (with obligatory bottle opener).
For the nerdy inclined you can also get a USB drive bottle opener.
