Tough question to answer, there’s a lot of skills to choose from. Definitely be one of the Core Fitting Skills.
I’m thinking Capacitor Systems Operation to maximize capacitor recharge rate. That extra 5% reduction in capacitor recharge time might be all that’s needed to make a good cap-stable ship fit.
rofl. (genuinely laughing, NOT an aggression)
BTW did not check the skill but I think if it’s 5% per level, then lvl 5 is “cap recharge multiplied by 100/(100-25)” so * 4/3 ; while lvl 6 would thus be "cap recharge multiplied by 100/(100-30) so *10/7. All in all it’s a gain of 7.1% in cap recharge for the level 6 !
i think (up to)51km web range ashimmu is more interesting, esp with upcoming 10% medium beam range buff.
what about minmatar core subystem, to make the loki OH web range higher ?
Salvaging to lvl VI guaranteed officer mod from any wreck in any part of space.
You are dreaming, while other people discuss serious consequences within existing game mechanics…
Might as well get recon skill and have fun with all the lachesis/arazu, rapier/huginn, curse/pilgrim debauchery, enforcer suddenly doesn’t suck that much…
Having skill that applies to multiple nice hulls in nice.
I would have to say Gallente Cruiser VI
Reason, that 11th drone on a Gurdian Vexor
Real reason, cruisers have a large verity of ships and Gallente ships are my favorite style.
Sadly that’s not how salvaging works. You would have a bigger chance to salvage successfully within one cycle but the results of salvaging are not based on any skill at all, if I remember correctly.
I’d pick Logistics Cruiser VI. Going from 75% reduced activation cost to 90% reduced activation cost for reps is going to be ridiculous!
I think any of the triglavian ship skills wouldnt be bad either especially the dessie or BC with the large bonuses they get per skill level.
The Abaddon would actually be fun to use!!!
Regardless of “level VI” and its statistics, the idea in general is interesting as a game design: right now with unlimited time or skill-injector money, you could theoretically train a perfect character. But if you could only push ONE skill to maximum per character, that would force specialization.
And it would make extractors suddenly the most popular item in EVE!
Bittervet VI for sure 
I think implants are kinda supposed to be specialized, and of course they cost a fair amount for the good ones.
Any of the racial Titans to 6.
Would love to queue that up, and just forget about my account for a year.
Neurotixin Recovery VI could be damn strong. Or Astrometric Rangefinding VI, for that slightly faster combat probing times.
Shield Management VI.
Writing VI
Okay maybe not a real skill but I’ve been trying to pen something cool and creative for the upcoming writing contest.
Maybe not a real game skill, no. But a real skill, above and beyond a game skill, nonetheless?
What upcoming writing contest?