well, better than telling there are lots of menu styles i thought i could post some of the links here.  so, friends you can enjoy the power of Joomla.

1.  Suckerfish style menu, Just hover on the menus , It is a standard menu system around the world and also in Joomla.  This is called suckerfish.

http://demotemplates.Joomlashack.com/weblogic/index.php?menutype=suckerfish

There can be any number of childs for this suckerfish.  But i have used until 3rd level.  Well ,  i think user will become tired of going to lots and lots of child menu item.

2.  Drop Line Menu Style

http://demotemplates.Joomlashack.com/weblogic/index.php?option=com_frontpage&Itemid=1&menutype=dropline

This is somewhat technically similar to suckersish, however, it displays sub items next to parent menu border generally.

I think only one child can be used for this style.

3.  RokMoomenu

http://demo.rockettheme.com/sep08/index.php?option=com_content&task=view&id=24&Itemid=38&mtype=moomenu

This style of menu is based on Mootools javascript framework.  If you think you want to make a nice user interface, better SEO and lots of child menus, then moomenus are generally nicer.

Basically Mootools are already included inside Joomla.  So, the size of Joomla template is also limited in size.

4.  SplitMenu

http://demo.rockettheme.com/sep08/index.php?option=com_content&task=view&id=24&Itemid=38&mtype=splitmenu

Split menu is very useful particularly inside Joomla cms.  The parent menu items will stay on top as usual.  The child menu items will get displayed on right side of template generally.  Of course, you can arrange them on left side too.  Only thing is they are splitted.

It is very useful when you want to manage menu items easily.  Because, when you click on the child menu, you can keep the active position for left side menus as well as top menu.  It is easy, effective and user navigation friendly.

5.  Menu styles from Joomlart

Without any doubt , Joomlart has been dominating the market with very nice templates and styles of course. They are providing lots of menu styles, I give some of them here,

JA Moo Menu
http://template15.Joomlart.com/ja_pyrite/?ja_menu=moo

This is a Recent work from Joomlart (September 2008)  Which works on the base of mootools.

JA suckerfish
http://template15.Joomlart.com/ja_pyrite/?ja_menu=css

There are other types of menus there.  You can browse to find more from that template itself.

6.  Here comes a platinum style , that is called yoomenu

http://demo.yootheme.com/sep08/index.php?option=com_content&view=article&id=68&Itemid=74

I am sure you will get surprised too see this style.  The style works on all browsers surprisingly including ie 6.  The advantages are many.  You can assign colors, icons , transitions styles. Wow they are cool.

Ok, We have seen different styles of menus.  Most of the menus seem to be compatible with the template they provide.  However, as a user and owner of website, you may want to use your own template or style and you may want to use these menus inside your website.  Of course, it is possible.  You can buy the template and use it in your own template.  I hope that does not violate the terms of template clubs generally.  Because you are paying them for that stuff.  Else, you can even ask them on this thing.  I mean website here as Joomla CMS based websites.