I just checked blender 2.53 (newest version) and here are in the import and export formats allowed.
Imports: dae, 3ds, buh, obj, mdd
Exports: dae, 3ds, fbx, mdd, obj, ply, x3d
This is from the newest version that I'm using right now. I checked and haven't found any ase plugins for 2.53 that have been made yet. Someone made mention of an ase importer but it's still quite unstable and they are working on it.