I am going to break it down by Price. My apologies if I missed someone's favorite application. Further I restricted this list to software that has general modeling capability. (Leaving out things like Bryce, Poser, Vue and Daz|Studio which can do some modeling but are not really designed to do modeling.)
As you can see 3D modeling can get quite expensive. Note that in the under $200 category you will probably want an additional program to render your creation.
Of these I have or have had Blender (Can't stand the interface.), Shade LE (Can't stand the interface.), Hex 2 (Use it for modeling), Carrara 5 (Upgraded to Pro), Carrara 5 Pro (Use it for everything but modeling but if I didn't have Hex I would use it for that as well.). I have demoed Lightwave (Like it), and 3DS Max (Think it is overpriced.). For someone starting out I do recommend Hex 2 (Especially if you can get it at <$50) as a modeler and for a beginner with 3D applications I highly recommend Carrara. (It gives you the most bang for your buck and is more than just an entry level 3D program but is at an entry level price.)
Free:
Wings3D
Blender (More than just a modeler)
Less than $200:
Silo ($109)
Hexagon 2 (Currently $2 or $32, regular Price $149)
Shade LE (Now called Standard $199.)
Less than $1000; Generally not restricted to just modeling.
Carrara 5 Standard ($175 (Platinum Club), $205 if you shop right or $249)*
Carrara 5 Pro ($385 (PC), $414(Shop right) or $549 full price)*
Amapi 7.5 ($750)
Ligthwave 9 ($895 (though you can usually catch a sale and save $100-$200))
Cinema 4D (Basic Version) ($895)
Shade 8 Professional ($900)
Rhino (modeler only) ($995)
Greater than $1000. Many require plug-ins and can run you in excess of $10,000.
Autodesk Maya ($1995 or $7995 plus plug-ins)
XSI ($1995 or $6995)
Cinema 4D, XL, Studio, to adding all plug-ins ($2195, $3495, with plug-ins can reportedly exceed $10,000)
Autodesk 3DS Max ($3495 +Plug-ins which can reportedly exceed $10,000)
Many of these packages do have educational pricing for teachers and students with restrictions on them, these are not those prices.
Also note that for some of these modelers you will also need or desire separate UV mapping software and a paint program for texturing.
*
Daz3D has an interesting pricing policy which for big ticket items means you never have to pay full price. Their platinum Club membership which costs $29.95 to join for a month will give you 30% off Daz products. (Plus some other benefits.) So the low price is for those that are members, the mid price includes an initial month of membership and the high price is the full price.