The high-tech climbing boot you haven't yet heard of: Zamberlan hit the mark with their 3030 Eiger Lite GTX RR Boa (henceforth "Eiger Lite"). Though the name is a bit of a mouthful, these streamlined boots offer top-tier performance for cold-weather climbing.
The Eiger Lite has a narrow fit compared to other insulated climbing boots on the market. It's a great boot for climbers with low-volume feet who find it hard to achieve a performance fit in wider models. Snug boots are important for technical climbing, so if your feet are on the narrower side, this boot will suit you well.
With a simple velcro closure on the upper cuff and a convenient boa system on the instep, it's easy to dial in the fit of the Eiger Lite. The external boa dial is especially nice for keeping the feet warm while belaying—it can be cranked down for maximum responsiveness while climbing a pitch, then loosened with the snap of a button to allow for full bloodflow to those frosty toes. All of this is concealed by a waterproof zippered gaiter that keeps snow out and warmth in.
Warmth is perhaps the greatest asset of the Eiger Lite. Even on days with temps in the single digits, I've had no problem keeping my feet warm while out climbing. It's a great ice-climbing boot for even the coldest days in Montana, or for winter mountaineering in all but the most extreme high-altitude applications. Yet despite its warmth, the Eiger Lite lives up to its name, ringing in at under two pounds per boot in a size 10. The cuff articulates nicely, allowing for a wide range of flexible movement on technical ice and mixed climbs. Overall, the Zamberlan Eiger Lite deserves recognition as a high-end winter climbing boot.
Available at zamberlanusa.com; $750.