I will also add my 2 cents to the pot for statistics sake: I was also in an LDR with my to-be-husband for 1 year.
But we were dating for 2 years before that and knew that the separation was only temporary. That 'light at the end of the tunnel' that Fras and Giga mention is the make-or-break factor for LDRs, and I've never seen an exception to this.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh