Description
A good telnet client.
Character Sets
If a telnet client supports it, it is possible to switch between a limited range of character sets using ANSI escape sequences.

As can be seen in the screenshot above, Putty offers three different character sets. ISO-8859-1 (sequences ESC(A and ESC(B), a line drawing character set (sequence ESC(O) and the SCO alternate character set (sequence ESC(U). The default character set which Putty uses, ISO-8859-1, can only be changed by the use through its Translation settings window.
Antialiasing
Unfortunately the a few of the more graphical characters shown above, particularly within the displayed SCO alternate character set, are distorted. This is because Putty turns on antialiasing by default.

Another view of these characters can be seen in the following screenshot, undistorted after antialiasing is manually disabled through an option in the Appearance settings window. The characters to focus on are the solid block like ones appearing in the rightmost character set.

External Links
Putty - The Putty home page.