"Recommended" requirements?

[Jetsetlemming]

What would be the requirements to turn everything on, would you say? Do you use Shader 2.0 or 3.0 effects in the game?
I'm currently playing with a 2.66 Ghz processor, 1 GB ram, and a Radeon 9250, and my FPS varies a whole lot, from 60 in some areas to 5 in some situations (it seems the game doesn't like it when multiple dynamic lights are around, like a lamp and my flashlight... maybe it was something else having the bad effect though, I only tested it in one area).
I'm playing on the default settings with shader quality set to medium (I did that before even trying the game normally, I'm paranoid about shaders ever since I bought a DX8 level video card. Who'da thought I'd later regret passing up on a Geforce FX? ).
Any recommendations to improve the performance in those "hard" areas would be appreciated, too.