The Westland Lynx has the speed, agility and survivability to match (or exceed) the UH-1 in the uses the Huey currently has. It's rated troop capacity (and hence internal cargo capacity) is half though, and buying British isn't really something the US government does unless they have to. The Wildcat is even tougher, but trades even more cargo capacity for onboard fuel capacity.
The Bell 525 is a civvie airframe which I've seen successfully co-opted for much of the same work the UH-1 does now (flown them a few times too - reluctantly, way too stable for my liking) - but survivability depends on how hard you believe in the crucifix hanging from the stick.
There's really not that many current airframes in that particular slot - the UH-1 was so successful it pretty much drove the competition out. Kamov has one, the Ka-60, but buying Russian is right out, for obvious reasons!