Unity needs a better Blender importer. The armatures mess up on importing and the animation is really glitchy, I.E. sometime won’t load.
So far I haven’t experienced any messed up armatures or non-loading animations when importing Blender files. In any case, Unity has no Blender importer; all it does is tell Blender to export the file as FBX. If there are problems, it’s due to Blender’s FBX exporter, so you’re complaining on the wrong forum. 
–Eric
Ah ok. So if I play with the fbx exporter I might have more luck with my armature?
The importing of Blender armatures works very well, and also the animations. All the problems I have seen users have are debt to some lack of knowlegde about Blender and/or Unity. Try first to learn some more about Blender and Unity, then search for tutorials here and in the docs. Then ask most concrete questions and maybe we can help you to get it. But don´t panic so fast, it works
This was supposed to be a reply to the post right below this one, lol. I hate how the “Post Reply” button is right next to the “New Topic” button. I think it might relate to what version of Blender I am using. I have used Blender for a very long time. The problem with Blender is that it is always changing and being updated. What I mean is, some parts of Blender get broken with a new release, i.e. the FBX exporter. Are you guys using the latest version of Blender? When I import my model, I can access the bone and animation, but the actual model does not show up. In fact, the only reason I was using an armature is because normal key frame animation does not work either. Some things do relate to Unity, I believe, but some problems relate to Unity too. Unity is probably responsible for not rendering the object that the bone is attached to, but Blender is probably responsible for the other things. Doesn’t matter enough to make a new topic over, this was an accident, but just my thought.
Version 2.48a here. If the mesh isn’t showing up, either you’re doing something wrong, or the Blender .fbx exporter is messing up. Unity has one .fbx importer, which imports all files from all apps (Maya/Max/Cheetah/Blender/etc.)…there isn’t any special Blender import code. Unity only animates bones, so naturally plain key frame animation won’t work (in any app).
–Eric
Ok, I get what you mean. So it is probably all Blender then. I thought there was a specialized FBX importer for each app. It was probably one of these problems where I’m making my graphics on a computer running Windows 7 Beta and loading in the stuff on a Mac PPC into Unity. Seems to be the worst compatibility between 2 computers I’ve ever seen.
Huh? You can move/scale/rotate objects by keyframing them no?
I must be misreading what you said. You can definately use plain keyframe animation in any app.
Just in case anyone reads this wrong.
AC
Can’t do it in Blender, I’ve tried.
Oh ok so its static objects and bone driven animation only in blender? I stand corrected 
AC
I found that if your object doesn’t show up in Unity as soon as you’re using bone animation then there’s something wrong with your vertexmap/bone skinning. All polys not properly applied with a definitive vertexmap won’t show up when using animation as soon as the object’s in Unity.
A quick note regarding the FBX exporter for Blender: If you run into issues with this the person to contact is “Cambo” on the Blenderartists forums. He’s the original author and has been pretty good at updating the script as necessary.