How do I remove the 'tags' block from a product page?
If you are using a local.xml then just use this code:
<remove name="product_tag_list" />Using local.xml is the easiest way to modify your page. Also the best way btw. Better then just disabling it via backend. Via xml it doesn't load so in the end performance of your shop is better.
which tag.xml did you comment out? The one in your custom theme or the default? You need to do both, otherwise the default layout simply reinserts the values you omitted.
The <catalog_product_view> node in tag.xml is the one you are interested in.
I suggest that you read the article @Alan wrote on Magento XML Layout and install the LayoutViewer extension (or buy CommerceBug) to check that the layout updates are not being inserted then report back here if you still have questions.
HTH,
JD