I agree with Daniel agreeing with used. I do want to read AvX, but that would be quite a bit to start with.
I went searching for a few other ideas, but nearly everyone I found is a lot longer than I thought they would be. I included them anyway along with page length. Most I haven't read yet, but I did include Kingdom Come and Marvels because I can't recommend them enough. Most are on par price-wise with what X-Men Noir was.
The Infinity Gauntlet, 256 pages
Daredevil: The Man Without Fear, 224 pages
Astonishing X-Men, 320 pages
The Marvels Project, 208 pages
Ultimates, vol 1, 160 pages
Batman: Arkham Asylum, 216 pages
Kingdom Come, 232 pages
Marvels, 248 pages