This page contains most of the resources that I use and recommend.

Modeling Resources

These tools enhance productivity in modeling.

GrowFX

GrowFX is one of the coolest plugins your ever own when it comes to generating plants and foliage. I can't imagine a life without this one!

PolygonMap

One of my new favorite plugins for planar mapping. If you are using Max for level design... you need this plugin. It can make working with UVs on brush geometry feel a little more like home for Hammer users.

Power Nurbs

Power Nurbs is also one of my favorite plugins. It gives you really cool design tools and a more natural way of modeling organic architecture with a boolean process using Nurbs. The internal Nurbs tools in Max, sadly, suck. With Power Nurbs, you can actually use Nurbs in Max easily. Furthermore, it adds Power Sketch, which allows you to create spline shapes with options (like inference and curve styles) that become indepsensable once you learn about them.

Marius Silaghi's Plugins & Scripts

Marius Silaghi has several extremely useful plugins and scripts for modeling in Max. I have and used the scripts: Smooth Edges, Subdivision Reversion and Quad Connect. I've also used and endorse these plugins: TurboSmooth Pro, TurboReverse, Form, Jiggle and Deformation Cleaner.

Ant Stitcher

Ant Stitcher allows you to sew the edges of different polys, even if they don't share the number of edges/vertices to be sewn. Very handy.

Itoo's Glue

Glue (not to be confused with the Glu Fluid System) allows you place objects onto the surface of another object. While there are already ways to do this inside Max, it allows you to do it conveniently; I use it mainly to make a spline conform to the shape of another object's surface since it has better performance than space warps like Conform. It's also free.

Materials & Textures

Bitmap2Material

If you have to choose one and only one plugin for texturing in Max, get Allegorithmic's Bitmap2Material. Wall Worm has several tools designed specifically for it.

GeoMaps

Other than Bitmap2Material, I use the Curvature map in Boomer Labs' GeoMaps. It is great for creating edge masks or geometry-based texture changes.

Blur Beta

Blur Beta is a collection of many free plugins for Max, including some textures that I use commonly.

Rich Dirt

Rich Dirt is a really cool material system for adding weathering, wear and grunge to your geometry.

Productivity

Miauu's Work Plane

Miauu's Work Plane is one of my favorite new utilities. I cannot imagine living without it anymore, especially for level design. It allows you to easily create grids based off of object elements; the grids can rotate on their major axis lines based on the viewport angle. It's a commercial script, but very inexpensive. You'll find it well worth your money.

Zookeeper

Zookeeper is probably one of the most powerful productivity tools I own. If you haven't gotten used to it, it's really hard to understand exactly why you'd want it; it gives you entirely new ways of managing scenes. I highly recommend this program.

VFB+

VFB+ enhances the Virtual Frame Buffer window (you probably think of it as the Render Window). It has several functions, but the feature I enjoy the most is the ability to compare renders side-by-side with ease.