I have two bags that I really like. (1) The
Carradice Super C with a KlickFix easy release. (2) The Ozette Rando Bag by
Swift Industries.
The Carradice load is carried on the bars, so you'll need to take that into account because the weight will affect handling... not a lot, in my experience, but it's still a consideration. The KlickFix release system is easy-peasey and works like a charm. There's also a handy attachment under the bag to support a light, which is a great feature.
I don't have mine mounted at the moment, but here it is on the Peugeot I was running it on for quite a while. Note how high it sits.
The Ozette Rando is the best front bag you've never heard of. Custom colors - so you can be as classic, retro, or modern as you want to be. Available in waterproof waxed duck, I think. And you
won't experience any of the problems I ran into with one of the other companies trying to actually order a bag! The configuration is more typical of a rando bag than the Carradice, but the Carradice is a much less flexible sidewall construction (think: great way to carry my camera gear!) You will need a front rack and
decaleur with the Swift Bag, so that will add to the cost if you don't already have the hardware - however, the load is off the bars and on the rack, and doesn't interfere with hand positioning.
Here's the Ozette Rando Bag by Swift on my Boulder. Note that the load is lower and supported by the rack. I fabricated my own
decaleur, by the way, which is secured to the VO rack.
I love the roominess of this bag and highly recommend it.