Various options to store your SharePoint Solution’s Configuration Data.

The various options are : -

1. Code
2. web.config
3. SharePoint List
4. External Data Source
5. Property Bag - 
6. Hierarchical Object Store

Ref:
1. http://blogs.msdn.com/b/zwsong/archive/2012/03/27/where-should-you-store-your-sharepoint-solution-s-configuration-data.aspx - Good one with comparison. Do read the comments.

2. Hierarchical Object Store in SharePoint 2010 - more info on how to use the same.