3DSMAX import / export

I'm working on a project at the moment, and I'm finding the import/export of 3DS to be a major limitation with 3D Studio Max. I was wondering what other formats and plugins were available (for free) to allow me to work in more thorough formats.

I realise that when exporting characters to blitz I'm best using the SMD exporter, but is this suitable for environments as well as just characters? Would this retain my smoothing groups, and hierarchy when imported back into Max?

Basically I'm trying to keep a trouble free working method as I import and export between Unwrap 3D and 3D Studio MAX. There's a lot of free export tools, but very little that will let me get the shape back into MAX for further tweaking.

Milkshape then convert to b3d with the milkshape plugin

Is there a milkshape importer for 3D Studio Max 4/5?

That's what I'm asking about mainly. I've discovered a Wavefront OBJ importer/exporter for MAX. I'm yet to test this, so I don't know whether this holds any advantage over 3DS.

Which is the best file format to import into MAX, to retain model features such as texture co-ordinates and smoothing groups?

I would say: you are mad to try and have Max at the end (or middle) of your modelling process. It's really good for the start of it: modelling and even UV mapping/texturing. But, it really isn't that good for importing and exporting.

What kind of tweaking were you thinking of?

The big advantage of import/export via obj is that quad faces are preserved. Exporting to 3ds causes all polygons to turn into tris.