Depends on the smilie, really.

Text smilies I enjoy using
=|
=[
=]
>=]
D=!
>=o
=o
>_>
<_<
^_^
>_<
¬_¬
=/
;D
o_o;
o_x and >_* and >_x etc. etc.

Graphic smilies I enjoy using
/
/
/
/
/
/



There might be others I use on occasion but that covers the most of 'em.