You dealt with it when Apple switched you from MFS to HFS, and again you were switched from HFS to HFS+ (and even journaled HFS+), and you'll deal with it again: according to Sun CEO Jonathan Schwartz (whom you may know for his totally righteous pony tail), Apple is going to use Sun's crazy advanced ZFS filesystem when they move users over to Leopard. The material advantages may not be immediately apparent to the average user (when was the last time you whipped up a multi-exabyte file?), but it will do some excellentay things like storage pooling (aka virtual storage), block-journaling, and plenty of other nerdy things about which you can read up on elsewhere. Expect to hear more about this one next Monday at WWDC.
Watch - Schwartz talks it up [Via MacRumors]
Read - More about why this is a Good Thing (TM)