Skill cap for Borderlands

There are a total of 105 talents to skill up in. You start gaining skill points at level 5.

From the Borderlands wiki:

If the player uses an unmodded character and does not have any DLC, the player will have accumulated 54 skill points by the time they reach the maximum level of 58. However, with the addition of the Mad Moxxi's Underdome Riot, The Secret Armory of General Knoxx DLC, and Claptrap's New Robot Revolution, it is now possible to attain a maximum of 69 skill points (2 extra from The Underdome, another 2 from Claptrap's Revolution, and 11 extra from The Secret Armory).

If you use an editor to change your character, you can actually add 105 skill points and fill up the entire tree.

So to answer your question(s?), 105 is the maximum required to fill up all the trees and 69 skill points is the maximum you can attain from the GOTY edition.