The Invulnerability powerset has elements of both Damage Resistance and Defense in its' powers. It also includes a very nice heal with Dull Pain and an Accuracy buff with Invincibility. When City of Heroes first started, there were a multitude of possible ways to play an Invulnerability tanker. It was possible to pick and choose powers, which resulted in both a wide variety of builds and numerous arguments on the COH Forums about what powers were better and which were really necessary.
Unfortunately, the large number of changes in the powers since launch has resulted in narrowing the choices of builds available to the Invulnerability tank. The only real differences between most builds these days are the power pool picks and the Ancillary pool pick.
Unyielding at level 8 and Invincibility at level 18 are still the mainstays of the set. Experienced players will recommend taking Temporary Invulnerability at level 1 rather then Resist Physical Damage due to the extremely small benefit from RPD. Several respected players even advocate not taking any of the passive resistance powers due to the small benefits they give now. I don't agree with that, I am a firm believer in maximizing my primary powers, but it is certainly a viable option and allows more power pool or secondary powers to be chosen.
I enjoy Super Strength because it has a comic book feel. When you hit someone with Knockout Blow and they fly 20 feet up in the air, or use Foot stomp and a dozen mobs fall to the floor, it really feels like you are a super hero. Once you have Rage, and make it perma, the SS damage output is quite respectable.
There are some good reasons for taking attacks like Handclap and Hurl, the former making a decent panic button for removing mobs from your area, the latter being useful in PvP because of the -Fly component. Handclap can generate decent aggro, since it is an AoE, but the disorient and knockback make it a poor choice for an opening move against a group in my opinion.
Next time I get around to doing a respec, I will probably change Rage to 6 slots, with 3 each of Recharge Reduction and ToHit Buff. The present slotting was mainly an experiment that didn't really fail, but is not as good as the 3/3 slotting that is standard. And since people insist on attacking me for no reason in PvP, the extra Accuracy will come in handy.
I didn't pick up any attacks from the power pools, mostly since I already have plenty to keep me busy. The 5 attacks plus Brawl seldom leave me with a shortage of attacks, and I also have the 2 range attacks from my Ancillary Power Pool to fill in.
Transportation powers are very much a matter of taste. I have always picked out travel powers to fit the concept of the character. Since Justice Blues is in the Iron Man mold, Flight was the obvious choice. He has had it since I created him, even when it was Unyielding Stance rather than Unyielding.
The Fitness pool, while not the requirement it was formerly, is still very useful for an Invulnerable tank today. Swift was chosen over Hurdle in part to keep up with the Super Speed blasters in missions and also because Fly takes care of any necessary horizontal movement. Health in combination with the large number of tanker hit points and the hit point boost from Dull Pain helps create the regen tank required by the low effect of the current passive resistance powers. Stamina helps keep up all the toggles and attacks needed for tanking.
Arctic Mastery was chosen for character concept. Chilblain is quick firing and helps slow down AVs and bosses. Block of Ice is really nice against Sappers and stacks well with the hold from Knockout Blow against bosses and AVs.
Aid Other was chosen solely to hunt for badges. It is doubtful he will ever actually get one of the healing badges, since the power was chosen so late, but anything is possible.