Some sprite animations benefit from using a 3D texture, i.e. put frames on top of each other in a single 3D texture and animate by adjusting the R texture coordinate. This has the advantage that you can get linear filtering between frames.
It depends on the type of animation how it will turn out, though. Something like a character animation would look rather bad but effects like explosions, fire, smoke, etc. look very smooth. You can get away with fewer frames or play an animation slower without stuttering.
I've been experimenting with this a bit lately. If you want to see how it looks in comparison, try this:http://ciardhubh.de/download/node/19/3DTextureAnimation.jnlp
The top two quads are textured using an array of individual 2D textures. The lower two are textured using one 3D texture.