Unicode greatly enhances the interoperability of information, removing the very problematic need to associate a character set with your data. One really should make an effort to use it when possible. Unicode in combination with standard presentation languages like xhtml will obviate the need for proprietry information formats like Microsoft Word for example. Personally I started using unicode as of red hat 9, where it was enabled by default. Everything just worked™ (see how cool it is ☺) For the record my LANG environment variable is set to en_IE.UTF-8 Note UTF8 is an…
Unicode greatly enhances the interoperability of information, removing the very problematic need to associate a character set with your data. One really should make an effort to use it when possible. Unicode in combination with standard presentation languages like xhtml will obviate the need for proprietry information formats like Microsoft Word for example. Personally I started using unicode as of red hat 9, where it was enabled by default. Everything just worked™ (see how cool it is ☺) For the record my LANG environment variable is set to en_IE.UTF-8 Note UTF8 is an efficient unicode encoding (for english and european languages at least) and is the best one to use in my opinion. There is a good description here of commonly confused characters which is more of a problem now we have unicode. Also Joel Spolsky has a nice timeline summary of character encodings. Given the huge amount of unicode characters available I found it quite difficult to find a particular character. To this end I created the table below, from which you can cut & paste. Note also there is a very handy character picker applet that comes as standard with gnome. You can populate it by pasting from this page or the excellent gnome-character-map for e.g. This is a screenshot of the characters I’ve populated it with. Once you click on your required character it’s copied to the clipboard for pasting into the application of your choice. 
Currency
¢ 0x00A2 cent
£ 0x00A3 pound
¥ 0x00A5 Yen
€ 0x20AC euro
Misc
° 0x00B0 degree
℃ 0x2103 Degrees C
¹ 0x00B9 superscript 1
² 0x00B2 superscript 2
³ 0x00B3 superscript 3
… 0x2026 horizontal ellipsis
☹ 0x2639 sad face
☺ 0x263A happy face
© 0x00A9 copyright
™ 0x2122 trademark
á 0x00E1 a fada ;-)
← 0x2190 left
↑ 0x2191 up
→ 0x2192 right
↓ 0x2193 down
↔ 0x2194 left right
➊ 0x278A ➋➌➍➎➏➐➑➒➓
Mathematical
± 0x00B1 plus minus
× 0x00D7 multiply
÷ 0x00F7 divide
≈ 0x2248 almost equal to
≠ 0x2260 not equal to
≡ 0x2261 equivalent to
≤ 0x2264 less than or equal to
≥ 0x2264 greater than or equal to
∴ 0x2234 therefore
∵ 0x2235 because
α 0x03B1 alpha
β 0x03B2 beta
π 0x03C0 pi
µ 0x00B5 micro
∞ 0x221E infinity
Control Symbols
␀ 0x2400 Null
␛ 0x241B Escape
␈ 0x2408 Backspace
␡ 0x2421 Delete
␉ 0x2409 Tab
␊ 0x240A Line feed
␍ 0x240D Carriage return
 0x2424 New line
␠ 0x2420 Space
␣ 0x2423 Space graphic
␝ 0x241D Group separator
␞ 0x241E Record separator
␟ 0x241F Unit sepatator