The Kata line is really well built. Also check out the LowePro Line. I had the FastPack 350 and I found it nice as well. You may not need the 350, but the 250 should be good. Just depends on how big a bag you want.
I can vouch for the Lowepro line... I have the Lowepro runner and while containing the dslr in the main room opened from the front, the back has a side pocket with ziplock that can contain a mbp or an iPad with no problems.
Also the Runner comes with a build in raincoat, so you can have it with you in all weather.
They also come in various sizes, so no need to get scared by the amount of space in this one
Kata 3n1-22: Big enough for my D7000, battery grip (attached), 3 lenses, flash and accessories... and that's without going into the "general" section at the top of the bag. The laptop section is only big enough for a Macbook Air (and and probably only the 11" at that) a small, thinnish netbook, and is perfect for an iPad in a case.
As you can change the straps from a quick access sling to a full on backpack it's since become my main bag. Plus add-on's like the tripod holder really make is a go anywhere solution.
Might suggest looking at the Think Tank Sling-O-Matic 20 or 30. The 20 has a front pocket that the iPad fits in; and the 30 has a dedicated laptop sleeve.
also depends on your budget. F-stop and Clik-Elite bags are well built as well, but aren't that cheap. I am hard on my equipment, and the LowePro line has held up very well, as has my Columbia bags..