Some tips to beautify your WeeChat, using unicode chars and some colors.

Unicode chars (your locale must be UTF-8)

A full line for separator between prefix (usually nick) and messages:

/set weechat.look.prefix_suffix "│"

Full line for read marker:

/set weechat.look.read_marker_string "─"

Arrows for join/quit (be careful, impact on log files):

/set weechat.look.prefix_join "▬▬▶"
/set weechat.look.prefix_quit "◀▬▬"

String for bar item "buffer_filter" (WeeChat >= 0.3.6):

/set weechat.look.item_buffer_filter "•"

"More" indicators in bars (WeeChat >= 0.3.6):

/set weechat.look.bar_more_down "▼"
/set weechat.look.bar_more_left "◀"
/set weechat.look.bar_more_right "▶"
/set weechat.look.bar_more_up "▲"

Colors (for WeeChat >= 0.3.5 with a terminal supporting 256 colors)

Time with gray shading, and no colon separator (WeeChat >= 0.3.5):

/set weechat.look.buffer_time_format "${252}%H${245}%M${240}%S"

Note: updated in WeeChat 0.4.2, the syntax is now:

/set weechat.look.buffer_time_format "${color:252}%H${color:245}%M${color:240}%S"

Another "blue" for background of title and status bars:

/set weechat.bar.title.color_bg 60
/set weechat.bar.status.color_bg 60

Some dark colors for delimiters, host,...:

/set weechat.color.chat_delimiters 29
/set weechat.color.chat_host 24
/set weechat.color.chat_prefix_suffix 24
/set weechat.color.nicklist_away 244
/set weechat.color.separator 60
/set irc.color.reason_quit  244
/set irc.color.topic_new  36
/set irc.color.topic_old 244

More nick colors: add for example "31,35,38,40,49,63,70,80,92,99,112,126,130,138,142,148,160,162,167,169,174,176,178,184,186,210,212,215,247" to nick colors:

/set weechat.color.chat_nick_colors "cyan,magenta,green,brown,lightblue,default,lightcyan,lightmagenta,lightgreen,blue,31,35,38,40,49,63,70,80,92,99,112,126,130,138,142,148,160,162,167,169,174,176,178,184,186,210,212,215,247"