If you use the 2.6 kernel, and are happy with applying other patches to it, I recommend the ck patch to go with it.
http://ck.kolivas.org/patches/2.6/
Most of the features have already been implemented in the 2.5/2.6 kernel, but there's a few things missing that means some bits run slower on this than they did on a patched 2.4.20 one. This should sort it out.
I haven't tested it yet, but will do when I reboot.