Commuting into London yesterday and travelling around during the day I'd agree no worse than normal. In fact, if you're not at the main Olympics venues it's actually a little quieter since a lot of people are staying away.
Use the underground to get around, rather than taxis, the streets *are* quite a lot more clogged due to the Games lanes.
You don't say what country you're based in, but check with your official distributor, there might be some tickets left for something, especially if you're prepared to pay for one of the more expensive seats.
My view - there's such a buzz in London right now I'd come if you can.