There is a wide variety of Montblanc writing instruments available.
In Practice, However, nearly all Montblanc sales are represented by three different pen types.
This page is designed to provide a very basic, one-page, easy to understand, introduction:

Click the Picture to view the Generation gold trim pens.  This is Montblanc's "entry level" pen... the least expensive, and therefore very popular.  The ballpoint, rollerball and mechanical pencil are all $230.00[v] and the fountain pen is $300.00[v]

Click the Picture to view the Generation platinum trim pens.  This is essentially the same pen, but with platinum trim.  Platinum, being a more valuable precious metal than gold, comes at a slight premium.  Ballpoint, rollerball, and pencil:  $245.00[v]; Fountain pen: $330.00[v]

Click the picture to view the Meisterstuck Classique gold trim pens.  The four most popular pens are at the top of the page.  This is Montblanc's "flagship" pen, and as such is just as popular as the Generation, if not more.  This is the pen that one might think of when "Montblanc" is mentioned.  The ballpoint, rollerball and pencil are all $385.00[v] and the fountain pen is $515.00[v]

Click the picture to view the Meisterstuck Classique gold trim pens.  The four most popular pens are at the top of the page.  As with the Generation, this is essentially the same pen, but with platinum trim instead of gold.  Ballpoint, rollerball, pencil: $395.00[v];  fountain pen: $540.00[v]

Click the picture to view the Starwalker series.  This pen enjoys popularity because of its contemporary look.  Montblanc tends to have a very classic look about it, and pen styles seldom have an avant garde feel to them.  The Starwalker is an exception.  The trademark star... the "snowflake on the mountain" - which is Montblanc's trademark - is suspended in a transparent, acrylic dome, which tends to be popular among buyers who tend towards the contemporary.  There are two types of starwalker pictured on this page, resin and metal/rubber.  Only the resin pens can be engraved.  The Starwalker resin ballpoint, rollerball and pencil are $385.00[v], and the fountain pen is $515.00[v].  Only platinum trim Starwalkers are available.  There are different styles of the Starwalker available (Cool Blue, Black Mystery, Platinum Doue, etc.)  Call for details.

Beyond that, there are many more pen types available.  However beyond the above five pens, the price rises exponentially. 

With respect to engraving, setups and run charges can be found here:

http://www.mombreaproductions.com/engraving/engraving.htm