2.6.27: loads ath_pci instead of ath5k
Since the upgrade to the new 2.6.27 kernel, the old madwifi driver (ath_pci) for my wireless card is loaded again instead of the new ath5k driver. With 2.6.26, it loaded ath5k by default. Ath5k works better than madwifi (faster association, connection more stable).
For now, I have blacklisted the ath_pci module.