Can I configure my Linux system for more aggressive file system caching?

I am neither concerned about RAM usage (as I've got enough) nor about losing data in case of an accidental shut-down (as my power is backed, the system is reliable and the data are not critical). But I do a lot of file processing and could use some performance boost. That's why I'd like to set the system up to use more RAM for file system read and write caching, to prefetch files aggressively (e.g. read-ahead the whole file accessed by an application in case the file is of sane size or at least read-ahead a big chunk of it otherwise) and to flush writing buffers less frequently. How to achieve this (may it be possible)? I use ext3 and ntfs (I use ntfs a lot!) file systems with XUbuntu 11.10 x86.