Lots of votes for Rozel (2013-05-18), and that's probably my personal best chase too. Still, when throwing around a word like "perfect," I can't help but aim a little higher than a storm that was absorbed into a squall line less than an hour after its first tornado -- and was surrounded by underperforming, high-based, nontornadic dryline convection.
Days that seem like candidates in my mind, even though I witnessed none of them:
- May 29, 2004 (Harper-Sumner Co., KS). This seems like the best southern Plains storm in the modern chasing era, with somewhere around a dozen intense, high-contrast, photogenic tornadoes of all shapes and sizes over perfect terrain. If you were on the storm from the first tornado and played it well, this would be hard to top for the rest of your career.
- June 24, 2003 (Manchester, SD). This is probably the northern Plains' answer to Harper Co. 2004. Again, countless tornadoes from a single storm, several of them photogenic and spanning a wide array of shapes and sizes. The Manchester tornado itself was of course more jaw-dropping than any individual tube on Harper Co., although there probably weren't as many true quality tornadoes with this storm.
- May 31, 2010 (Campo, CO). Only one really noteworthy tornado, but in my mind, it's probably the best tornado since at least 2000 for chasers. Among the top 3 most beautiful on record, barely moving, crossed the major paved highway at a snail's pace, deep blue skies behind the storm. This will probably be the gold standard for photogenic tubes that I'll spend the rest of my chasing career trying in vain to match, unless I'm extraordinarily fortunate.
Those are really the top tier in my book, at least since 2000. If you allow for just one or two faults (storm motion, rain-wrapping, haze/cirrus reducing contrast, terrain/population/roads, sunset before the best show ended) on otherwise awesome days, the book opens up way too much... Pilger, Coleridge, Bennington, Rozel, Langley/Salina, and Tipton/Manitou all just in the past few years and off the top of my head. Don't get me wrong -- I'd be elated to have just one day in that realm this spring. But for the three I listed, I just can't think of anything significant to complain about for those who were on the storm, no matter how high your standards.
One note about some of the X-factors like rarity of location, season, lack of chasers in the vicinity, and overperforming low expectations: those are all positives to me, and on most days they play a huge role in how happy I am with the result. It's often more enjoyable to go out with zero expectations close to home and see even a short-lived tornado or awesome structure than it is to see a "decent" but unmemorable tornado on a HIGH risk you lost sleep over for a week leading up. But at the very high end, I think a lot of those factors start to fall away for me, at least to the point that they'd only be a negligible cherry on top. If I played Campo or Harper Co. perfectly, the fact that there were lots of other chasers around or that it happened in the traditional season and region wouldn't even enter into the equation -- it would still be my favorite chase, I imagine.