The title pretty much says it all, plain text files are a bit annoying to read on QuickLook (and to preview on finder's preview column) due to a lack of antialiasing.
On the General preference panel I've checked that my text smoothing is set to ~“Turn off for sizes 4 and smaller”.
I've also checked with TextEdit that the font size in QuickLook is quite on the bigger-than-4 side, and that I can see the text antialiased in TextEdit.
Doing some googling I only found people with the same need but 0 solutions.
For the record: this is a brand new mac with OS X Lion 10.7.2 as fully updated as I can, that arrived home last week and I haven't (yet) installed any plugin at all for QuickLook.