I have been offered a very good price on a slightly used Canon 350D with a Sigma 18-125 mm. f/3.5-5.6. The price includes a battery grip with 2 batteries, and it's 500 dollars less than the new price total here. I need to know if this lens can be used as a good all-round lens. My first real trip with it will be in August to China, and I'll be wanting to take lots of street scenes. Will I be happy with this lens as a first, all-round lens while getting to know the camera, and my first big trip with it taken into consideration? I finally decided on the 350D over the 20D on a combination of size and price. I need the camera to be small enough that I'll really take it with me, and the price difference means I'll be able to get better glass, faster. All opinions appreciated!