Good to dee you here, Bruce. Sorry no one answered your question right away. Cameras don't inspire quite the kind of passion as mountain bikes do, I think

Of the three cameras you mentioned, I'd probably choose the G7. I really, really like having a compact camera with image stabilization. I think it makes a huge difference in the number of successful photos you get - especially if you are riding and shooting in the trees or at sunset. I've been using a Canon PowerShot A640 recently. I'm not 100% positive, but I think it's basically a simplified version of the G7. It has a 10-megapixel sensor, the shutter-lag is pretty minimal, and the image quality is excellent. I'd say that's a great, and less expensive alternative. You will be giving up the flash hotshoe and image stabilization, though. On the other hand, you'll gain a swivel LCD which is actually pretty useful.

I haven't used either of the other two cameras you mentioned, although we do have a Fujifilm super zoom on the way for review. I have used the Olympus SP-350 and I really liked it. For one, it's very small for a camera with all the features it has. It doesn't have the reach of the SP-550. But it will fit in a little case on your backpack shoulder strap. I think that might be tough for the 550.

I would also recommend looking at the Casio compacts. I don't think they have the best image quality. But the combination of compact size, speed, and features they offer is excellent. One of my favorite compact digital cameras ever was the Casio Exilim EX-Z750. It had full manual exposure controls and easily fit in a pants pocket.

Hope that helps give you a little more direction. I've been really busy working on other projects. But I should be able to keep a closer eye on this forum over the next few days. So if you have more questions, I'll do my best to make sure you get an answer.