I have two Altura front panniers, I forget the model. Not the waterproof line in any case. Those are probably too small for OP, but the quality is good, so definitely have a look into their larger panniers. I think they have a hook system with some kind of inserts, to accommodate different rack tube diameters. It's OK if you only have one bike, but a pita if you have several racks with differing tubing.

I also have a pair of Ortlieb rear panniers (the classic roller type). Great for all kinds of hauling, because they're really easy to clean, well designed and durable. Carradice products are great too, no experience on their panniers, but I have their saddlebag. The cotton duck + wax treatment has proved completely waterproof so far.

--J