Maemish: i recommend you to try 500-600: that's what i'm using for a while,
that's very smooth with a custom transitions.ini file, no tracker in home and devel upgrade, that's it
I only use 805MHz for specific multitasking or for pcsx_rearmed sometimes.

And indeed, Hildon-Desktop with Leste is now faster than Fremantle with stock freqs at least, with a good SDcard.

Maybe we should start a new thread for N900 customization and optimization ?