Also a decent band to check out that's somewhat influenced by Katatonia is "MARBLE ARCH-Another Sunday Bright". It was released on Century Media maybe 5-7 years ago and was actually good! Not great, but good if you like darker rock. I think the band broke up after the one release though.
NEW DAWN FOUNDATION is also another pretty cool band for darker rock. They sound a bit like H.I.M. but not as "girly" in the sense that they won't have quite as big appeal to girls as HIM does. Not knocking HIM for that though.
Edit: Both those bands are hard too find, but they are available on Amazon.com and maybe E-bay as well.