Cannondale Bad Boy / Mercian track / BOB trailer / Moulton recumbent project
I have the X-Press, and yeah, it's not the most confortable or visibility-firendly pack. But it is hellish tough and stoopid waterproof, for which I love it. If it ever falls apart, though, I probably wouldn't buy another one - I'd go for a Timbuk2 or a Chrome.
A thing to consider with those monstrosities is that when riding; you can not see behind yourself whatsoever. They stick way up above your shoulders.
Hmm, that's a factor I hadn't considered....I thought the top part of the bag could roll down. So you're saying that it still blocks your rear visibility even if the bag's not full? I'm not planning on having to ride with it filled all the way very much.