Narrowing down my choices for a conservative, business travel backpack

After months of browsing around (I'm in no rush) I think I've narrowed down my choice for a new backpack.

I have had a few criteria for the bag;
- very conservative looking, so I can bring it into a meeting if need be
- decent amount of space to handle all my carry on items
- external pockets for water bottle and umbrella (I work in the Caribbean a lot - both are necessities)

So, after checking out all and sundry, I think I have it narrowed down to three (maybe four)

This one from International Traveller fits the bill, at a decent price.

This one from Armor Gear is a little more expensive, but has mesh side pockets instead of neoprene, which I think may last longer (especially with sun exposure).

Then there is this Timberland one which comes with a neat removable, slingable sleeve, but is difficult to locate from a North American source (can't find any of these bags from a Canadian source actually).

I was also considering this Jansport bag as well, in black, but it has those stupid windows on the shoulder straps which detract from it's otherwise conservative appearance.

Anyone have any experience with any of these bags?