Which my.cnf file?

does anyone know which my.cnf file i should make changes in? i have about 5 of them.... i'm assuming its /etc/my.cnf but after adding a log slow query entry and nothing was outputed I'm wondering if that was the wrong my.cnf file.

also is there a site that you can input your server spec like how much ram and then it outputs the settings you need for the my.cnf file?

 

thanks. do you know of a site that tells you how to configure the my.cnf ... i have 3 gigs of ram on my server so I need an online configure script or help manual that tells how much memory each setting should have for 3gigs of ram systems

 

mysql.com is not all that helpful... they don't explain what each feature does and how to calculate the proper memory needed. i've been searching google all day. and i'm surprised that no one has created a simple program that reads your mysql processes and outputs recommended Options... I just need a listing of all the options and a diagram that says if you have 1gig ram then 32MB should be used for ever gig...