My best so far has been the UA AKL CNZ fare. I bought 6 tickets initially, had 3 cancelled, and flew the others. Used my SWUs to upgrade to F. Yes, I spent a lot of money, but I also consider the MR a ton of fun ( i got to meet Punki and Hunki and see SYD) but also had an amazing 10-day trip with my girlfriend.
However, the gain from that one thread pales compared to what I've gained from FT in general. I have flown over 350,000 miles in premium cabins over the last few years as a result of the research and understanding that FT has given me, and I find ways to redeem miles for awards that Joe Schmoe can only dream of.