It depends on what weapon you are using, and the other abilities you are using.
See, for an offensive roller, ink resistance up is great. If a roller can't move, he's dead. However, for a defensive roller, stealth jump is more useful, since it allows you to remain at key areas in order to protect them. Stealth jump with beacon sub-weapons is especially useful. However, an offensive roller might also want stealth jump if he is using a comeback ability, so he has more time to use his boosted abilities. In that case, Recon might work to replace stealth jump (which cannot be used at the same time as ink resistance), because you can then see if it is safe to jump, so there is less need for the stealth. You cannot have both recon and ninja squid, though (ninja squid is especially useful for rollers).
It's a tough decision. Place thought into your tendencies when playing Splatoon, and you should be able to figure out what gear optimizes that playstyle. In games like this, I tend to favor a more defensive weapon that has offensive capabilities if used with well-thought tactics. That's why I like the roller. I knew I would like the roller ever since the testfire. Once you pick your weapon, then you select the abilities that are good for it, further considering your playstyle.
Most of the greats of the abilities have been mentioned already. Tenacity has not been brought up, but is also useful. If an ally dies, your special weapon gauge starts to automatically fill up without you inking any turf. If you like to use your special weapon a lot, this is a good choice.
