Jon,
I wanted to run the raytracing benchmark myself to see if Haskell really was that slow. I'm using ghc 6.10 because that's what ubuntu comes with. I don't know if ghc 6.12 generates slower executables than 6.10 or what else might be going on. I ran each several times and the numbers I pasted are typical (+/- 0.2 seconds, say).

jeff@ubuntu:~/Desktop$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.4
jeff@ubuntu:~/Desktop$ g++ --version
g++ (Ubuntu 4.4.1-4ubuntu8) 4.4.1
Copyright (C) 2009 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

jeff@ubuntu:~/Desktop$ ocamlopt -v
The Objective Caml native-code compiler, version 3.11.1
Standard library directory: /usr/lib/ocaml

I compiled the raytracers for c++, haskell and ocaml from

http://www.ffconsultancy.com/languages/ray_tracer/code/5

and used the compile instructions at

http://www.ffconsultancy.com/languages/ray_tracer/benchmark.html

though I had to change the haskell one to use just ghc instead of specifying a version. I also ran the ocaml and haskell code in the 1/ directory, and they completed within 0.1 seconds of each other.

c++
jeff@ubuntu:~/Desktop$ time ./ray 9 512 > /dev/null

real    0m3.515s
user    0m3.440s
sys    0m0.016s

haskell
jeff@ubuntu:~/Desktop$ time ./ray 9 512 > /dev/null

real    0m5.811s
user    0m5.752s
sys    0m0.032s

ocaml
jeff@ubuntu:~/Desktop$ time ./ray 9 512 > /dev/null

real    0m6.572s
user    0m6.544s
sys    0m0.016s

Jeff