Constructing the Correct URL?

I've seen this question on the message boards but have never seen an answer so I thought I would post it here. Here's my dilemma... we are writing some customization that requires us to construct the URL to a record (e.g. and send it via email. I've seen a solution to this using Visualforce but never in Apex.

Here is what I came up with but it seems that there must be a better way. The only constant that I could come up with is our Production org ID. So my Apex class holds a reference to this ID and then I have a method that checks the current user's org ID and constructs the URL.

public class MyCustomClass {

 // set the production org id so we can see what system we are on
 private static final String PRODUCTION_ORG_ID = '00Z990000001ZZZ';

 // returns the correct system url for the current org
 private String orgUrl {
  get {
   return UserInfo.getOrganizationId() == PRODUCTION_ORG_ID ? '' : '';

 // write some code that calls orgUrl....