Apple has given the full-blown Tiger treatment to their website. Mac OS 10.4 ships on April 29th, but can be preordered now from Amazon, or the Apple Store. TUAW is running a poll to see which Tiger feature people are most looking forward to. Dashboard sounds great, but I think Spotlight is the one that really does it for me. Fast, full-text search baked right into the file system. Gotta love that!
Update: It’s worth noting that Amazon is offering a $35 rebate for preordering Tiger ($50 if you preorder the Family Pack, which is 5 licenses).