Unlocked multiplier does provide a lot of fun for me. I remember having fun on 975X* with ridiculously tight straps/timings using an E4600 when sky-high FSB was en vogue. At that time I didn't see any other Allendale chip that performed better than mine, clock-for-clock.
I also miss the A64 days when there were decent choices of multipliers at users' disposal and I would run calculators to squeeze the most out of my hardware, using multipliers and dividers.
Today things have changed a lot and overclocking is now more about brute-force.. for better or worse. I believe it's at least partially thanks to the huge headroom available in today's CPUs (though it looks like both AMD and Intel's 45nm hit the ceiling around 4.0 GHz) as well as shift towards more core counts, so maybe I shouldn't complain.. But personally I'm having less fun overclocking than I used to many years ago.
*Edit: 975X -> chipset, not CPU