Using WordPress widgets for your sidebar really makes things easy on programmers and especially on users. The only problem I have come across is customizing the widgets so that they work exactly how you need and look the best for your specific design.
I needed to manipulate the Tag Cloud widget so that the size of the largest font was not too big. It only took going in and changing one line in the widgets.php files. I wouldn’t suggest doing this unless you are somewhat comfortable with messing around with your code.
File to manipulate: wp-includes/widgets.php
wp_tag_cloud(); // at around line 1372
“smallest” is the size of the smallest font you want
“largest” is the size of the largest font you want
“number” is the amount of tags you want to appear
“orderby” is how the orders of the tags will be shown