I have a Lowepro Computrekker AW that I've toted around the world. It's a decent pack, the fabric sheds water, but the AW stands for All Weather, so it also has a built-in rain cover. It's got a a belt strap and chest clip, so it distributes the weight well.
It holds a good amount of photo gear and has room up front for extra stuff. It's got a laptop sleeve, but I rarely use it (great for magazines though).
There are a few things I don't like about it though. First is the way it opens. Like the flipside shown above, the whole 'front' opens up. So if you don't want the gear to fall out, you need to orientate it straps down. That is easy to do if you have a table, bench or if you are sitting on something. But if you're standing in a wet field, the only option is to lay the bag down, with the straps on the ground. That's not ideal because you have to put the bag back on. You can try to hold it and reach in, but that is awkward. For this reason, I don't like it so much for weddings, where I'd rather use a box shaped shoulder bag. The bottom is always the bottom and you can set it down and not worry too much.
Another thing about the Computrekker, is that when full, it's rather bulky and almost ball shaped. In other words, a lot of weight is far away from your body. A better design, is something like the Naturetrekker series, where the pack is wider and shallower, so the weight is closer to your body. This is better for long term comfort but it's also an issue when your walking in tight situations, whether it's trees or people....it's harder to move around when you have a big lump on your back, compared to something that is closer to your body.