APPOLYON  I like slider even though I don't use it all that often. While the sliding and the fading in/out effects are great, it takes a brief moment to complete. Not for the excessive optimizers.

A couple of things to note though. It doesn't play nice with Growl. It slides in the notifications nicely, but it flickers back into place slightly on the exit. Nothing harmful, just odd. Same sort of thing with InvisRay, except on the start. It flickers for a moment as it begins the display. Again, purely cosmetic, but worth noting. If you use Unsanity's APE you might as well try it out.  
(Version 1.3)

BDOG  This haxie is very cool! One thing I wish it could do. I have Up-Down selected as the slide style, and it won't slide the window down if the bottom of the window is close to the bottom edge of the screen (any 'full screen' window). The same idea holds true that it won't slide down a new window if it is near the menubar (although I don't use that bit).  
(Version 1.3)

MACSTERDAM  I like this a lot, but wish it could run independently of APE. Because of the latter I don't use it.  
(Version 1.3)