I've spent a couple of days now trying to figure out how to get a slideshow from NextGen Gallery to center on the center column to no avail.

Thus, I am asking for your assistance.

If I use the simple <center>[slideshow id=1 w=600 h=400]</center> it works in the browsers I have tried it in but I keep reading that it's not a good idea to use this for centering.

Anyone have a better solution?

Norm

nextgen has it's own CSS styling. You should look at the source of the page and find the gallery. Look for an ID or class that you can use and add a CSS to center it. (FireBug in FireFox)
Here is a link where you can read and test aligning block elements http://www.w3schools.com/css/css_align.asp

Try this...

Determine the width of your slideshow, then create a "div" and enclose the NGG shortcode inside of it.

<div style="width:350px; margin:0 auto;">
[slideshow id="x"]
</div>

Change the width to whatever works best with your slideshow image size.

This should work.