Taxonomy vs Values module in my case I'm using the Values module for creating a list of subscriptions the user can choose of when they register (it's a field in the registration form). Now I've seen I can also create a list with the Taxonomy module. I'm just curious what's the best practice for this? Should I use the module already implemented or is Values module better in my case?
The Values module is a field for users to enter their own list of values in a key-value format.

Core taxonomy module is used to create lists of terms which can be placed as a field on the registration form using a 'term reference'. This would then appear as either a select list, radios or checkboxes (checkboxes if the field is multi select). 

The difference is that with Values, users enter their own values and with term reference and Taxonomy, users choose from your list of terms in the taxonomy. Which do you want? I think if you're looking for subscriptions, it's term reference and Taxonomy.