This is something I see come up a lot when developing Sitecore websites, how best to reference your items, by path or by guid. Almost every method in the Sitecore API will accept both path and guid as will xslt (paths often been XPATH statements in that case). Both have their pros and cons and both are more suited for particular situations that the other.

The biggest benefit of paths is their human readability, even a non-technical person can find an item based on its path. If however you’ve spent a whole project referencing items by path and you need to change the site item hierarchy you’ll run afoul of a potential refactoring nightmare, doubly so if those paths are created dynamically. Guids on the other hand are the exact opposite, they’re essentially immune to 90% of those refactoring issues but they’re otherwise uttering incomprehensible (i.e. 5EBC6046-5012-4C78-BAC9-5852A8E26918)

So the long and short of it is that it would be nice to use guids everywhere for more robust code but you’ll need to hope everyone remembers to put a friendly comment in explaining what the guid is for. The middle ground solution I’ve found which really nails the issue for everything but xslt (more on that later) is a static settings class like below:

using Sitecore.Data;
namespace Example.Business
{
    public static class SiteSettings
    {
        public static class TemplateIds
        {
            public static TemplateID Client { get { return new TemplateID( new ID("5EBC6046-5012-4C78-BAC9-5852A8E26918"));} }
            public static TemplateID Branch { get { return new TemplateID( new ID("{35E75C72-4985-4E09-88C3-0EAC6CD1E64F}"));} }
            public static TemplateID Fees { get { return new TemplateID(new ID("{334CA6C3-B6CB-4A86-80C4-1BD1892408BB}")); } }
            public static TemplateID Service { get { return new TemplateID(new ID("{2FB9F53A-CCE2-4873-A376-BE1984FE0DDB}"));} }
            public static TemplateID Section { get { return new TemplateID(new ID("9F9AE8B7-159D-468E-9732-68BB7E9D53A4")); } }
            public static TemplateID Article { get { return new TemplateID(new ID("CCDAE7B5-656C-4E64-90D1-7A6BDC66C697")); } }
            public static TemplateID Author { get { return new TemplateID(new ID("D3B7113E-639E-494C-8F4D-65A4CADCE11A")); } }
        }
        public static class ItemIds
        {
            public static ID ArticleRoot{ get { return new ID("7438EA73-B93A-476E-B6A0-9FE4C382AE66"); } }
            public static ID Branches { get { return new ID("BAD98E0E-C1B5-4598-AC13-21B06218B30C"); } }
            public static ID SiteRoot { get { return new ID("D3978CE5-BBC7-4201-9D53-46B53E039365"); } }
        }
        public static class WorkflowIds
        {
            public static ID NewSection { get { return new ID("1FE1D278-6463-47AD-9813-E82C82F87753"); } }
            public static ID NewComponent { get { return new ID("777348EE-A748-47EC-B771-9BC0F5A0C636"); } }
        }
        public static class WorkflowStateIds
        {
            public static ID LoginDetailsSent { get { return new ID("DE94B240-198D-40BE-8621-236EF74DB395"); } }
            public static ID Approved { get { return new ID("3521F34D-F15D-404D-9EAB-DF124F89EE56"); } }
        }
    }
}

Straight forward and simple, the only downside is that it cant be used for your xslt renderings but more on that later…