I've had the most luck balancing comfort and performance with MX bars or at least MX style bars with a 50mm stem. Usually winds up being 22.2mm bars with a BMX stem. That's my preference for off-road riding
If sticking with the Velocity stem, and with an emphasis on comfort, and for street use and maybe gravel, I'd consider Nitto Albatross or something very similar. North Road style bars vary in the degree of forward sweep; I can do bars with no forward sweep at all (eg Nitto Bosco) if I'm using a 130mm (or more) stem; any less than that and I need at least some forward sweep. The Rivendell website has a good array of North Road bars so you can see your options (although if you're located outside the US, Blue Lug might be better in terms of shipping costs)
Lord knows I love the folks at Surly but I feel their prices are a bit much for what you get; among other things their handlebars are heavy. The heat-treated aluminum Albatross is only a little more money for something that's beautiful, light, versatile, strong, and should last a lifetime. I like the wrist position and really like that it'll take bar end shifters, which opens up some grip real estate. Gives ya two distinct hand positions -- one well forward of the steering axis for performance and climbing; and one out on the tips if you want to sit up and look around, or go downhill. You can also mount em upside down if you want to get all aero without having to figure out how to make drop bars work on a mtb frame. Only thing you gotta watch is, you have a lot of leverage at the clamp, not sure a Velocity stem will clamp em down tight enough for rough terrain. For street it should be fine but it'll need to be gorilla tight
