Price GRM-friendly is going to be the killer. Nikon has a zoom lens with a similar range that has a constant f/2.8 but that's more of a challenge friendly budget lens. There are a couple of aftermarket lenses in that category that are somewhat cheaper, though.
According to some of the reviews I've read from source I trust, the 18-55 is actually a pretty decent lens apart from the lack of low light capability. Better glass is relative then, the f/2.8 ones have to have better glass simply because they need to control the various aberrations better due to the larger glass surface.
I know you said 'no prime lenses' but the one I really like is the 35/1.8 Nikon. It's inexpensive, the f/1.8 is useful in low light and compared to the f/2.8 zoom lenses you're not carrying around a stupidly large hunk of glass around.
My other favorite lens on my D200 is the 12-24mm f/4 but that of no help for you (it's expensive and has a not so great F-stop).