Launcher Pro, my favorite launcher replacement, got updated today with a much requested feature - homescreen transition animations, available to all LP users, not just Plus. In addition to the usual and very smooth slide effect, we now have 4 more: Scale, Rotate, Flip, and Cube. All are smooth, except for the Cube transition, so I would advise against using it until Fede makes it a bit more snappy.
The virtual looping feature enables scrolling past the leftmost or rightmost homescreens with a quick bounce-to-the-opposite-end effect. While Fede implemented it this way instead of an endless scroll for technical reasons, I think it's visually a lot better and clearer, as you will still know when you've reached the end and won't feel lost in your own homescreen forest.