This is just a grab shot with the 500mm mounted on a monopod, but I have to say I'm pretty pleased with the result - 1/250th at f4, ISO 800. This was early morning in pretty mucky light, and yet I got away with it. I reckon my monopod is just about the most useful piece of non-electronic gear that I own, and I never travel without it - always in hand luggage. If my suitcase is delayed, I'm still good to go, and half the time I use it in preference to a tripod anyway, as the greater mobility is a real asset. If you're in the market for one but are not sure it's for you, I can recommend the Manfrotto 680B as a cheap, excellent and nigh on indestructible bit of kit.  If you're a believer already, don't mind shelling out, and want something more compact and yet utterly rock solid, the Gitzo 5561T is absolutely brilliant.