London, UK

Pro's:

• Ace Cafe
• Filtering is legal. If it wasn't, sitting in traffic in the rain would be unbearable.
• Police have better things to do than chase down motorbikes for minor things. And should they, are generally pretty nice.
• Actually affordable. With a car you have congestion charge, parking(and parking tickets), fuel, tax, crazy high insurance.
• Loads of other bikes to play with
• Winter isn't usually bad enough to stop you riding if you hate your bike enough and have balls for days.
• Drivers generally don't mind you existing, 30% will move to let you filter past (if they see you that is...) or they are so far behind you by the time they get annoyed that it doesn't matter anymore.
• Personally I like riding with/through the traffic. Keeps you from going at license losing speeds and you get into this rhythm that is quite relaxing. It really clears my head after a complex problem at work.
• You can explore so much more of the city than in a car or on foot/with the trains/tubes/buses. Getting lost on a bike in London is actually fun (outside peak times).

Cons:

• Rain
• Traffic (I work 10-6+ so I don't hit peak times often but still. urgh)
• Not many good roads. Bad if knee down is your natural sleeping position.
• Theft (park next to the R1 or S1000 and you'll be OK)
• You will be involved in a collision at some point.
• Perhaps with an idiot pedestrian not looking in case a bike might be filtering in that MASSIVE GAP between the bus and the lorry that have been stationary for 5 minutes.
• You can't just get on and go for a ride through the countryside. You have to at least go past the M25 first.
• You can never find a parking spot in Soho and you have to pay £1 a day for the privilege of riding around trying to find a spot in Westminster for 20 minutes (during the week)
• No Shed. I can't have that DRZ project bike I want and I do all my maintenance in the street.
• Did I mention Rain?