Pannier that converts to backpack

[PamNY]

I want a smallish pannier that converts to a backpack -- and is reasonably comfortable.

I'd be using the backpack for 2-3 hours, mostly birding. I've found several possibilities, but would love any recommendations.

[Blueberry]

Check out the Arkel Bug and Switchback. I don't have either, but do have some of their products and have been very impressed. They have higher prices than some, but (at least to me), their craftsmanship more than makes up for it.

[DebW]

A friend of mine has the bug and loves it. I've ridden with her biking to a hike, and the conversion was very quick. My approach has been to use a small day pack (http://www.rei.com/product/778466 which inverts so there are no loose straps and attach it to the top of my rack. The load is balanced rather than one-sided like a single pannier, but of course it takes some time to convert from bike pack to day pack this way.

[ummbnb]

Knog has one that I just bought and gave away in an employee alternative commuting weekly raffle. I think it was the "old dog" or something like that.

[PamNY]

Those Arkel bags look great. Since my clothes dryer just died it may not be the right time for something pricey, I will probably stick a day pack on the back rack.