What I'm about to say is probably bloody obvious, but I'm pointing out what the effect of each maxed skill would be. And don't forget mothership mods count towards that percent.

Advanced BioFarms: 255% (Thanks to Draken) = 35.5 credits per biofarm per turn
Advanced Locator: 255% (Thanks to Draken) = 3.55x segments on Extend missions
Time Dilation: 255% (Thanks to Draken) = Cap at 12,750 turns (assuming initial cap is 5000)
Planetary Combat: 255% (Thanks to Draken) = Marines are 3.55x stronger
Marine Leader: 70% (Thanks to Draken) = Marines cost 0.3 credits
Special Board Fleets: 255% (Thanks to Draken) = Ships hold 3.55x marines
Kamikaze Master: 50% (Thanks to Draken) = 1.5x attack on all ships
Unknown Alloy Armour: 70% (Thanks to Draken) = 1.7x HP on all ships
Slave Training Knowledge: 255% (Thanks to Draken) = ~1 credit per 850 workers
Master Defender: 50% (Thanks to Draken) = 1.5x defence on all ships
Black Market Dealer 37%(Thanks to Sir Emi and Draken) = Ships bought with the design cost 63% of original
Shield Master: 37% (Thanks to Draken) = ABS +37%
Target Tracker:   37% (Thanks to Draken) = ACC +37%
Emphatic Trade Relations: 70% (Thanks to Draken) = Market buy price x0.3
Fast Talker: 70% (Thanks to Draken) = Market sell price x1.7
Line Assemble: 80%  = Ships cost 20% of normal
Upgrades Dealer: 37% (Thanks to Draken) = Upgrade cost x0.63
Explorer Mercenary: 50% (Thanks to Draken) = 1.5x segment reward
Elite Mercenary: 50% (Thanks to Draken) = 1.5x credit reward
Slave Trader Mercenary: 50% (Thanks to Draken) = 1.5x worker reward
Contraception Ban: 255% (Thanks to Draken) = 3.55x worker growth rate
Bank Fraud Program: 255% (Thanks to Draken) = 3.55x interest
Genius Mind: 255% (Thanks to Draken) = 3.55x EXP
Genius Leader: 255% (Thanks to Draken) = 3.55x CP from levels
Alliance Genius Leader:   100% (Thanks to Draken) = 2x alliance size
Warp Alignment Sensibility: 75% (Thanks to Draken) = Travel cost x0.25

Putting all the stat boosts together gives you a ship that's ~10 times the strength of its original cost. Cool.