Vigor and Expansion are definitely good ones. In a team game dimension swap makes you the party's valorous hero really fast (since you take an ally out of danger in true self-imposed style). Of course, my favorite is again the Vigor + Psicrystal + Expanded Knowledge (Share Pain) to create a Tankmaster 9001.

Basically, you keep your Psicrystal on you. You manifest Vigor at full-power (1pp = 5 temporary HP, so at 5th level that's 25 temporary HP); share it with your Psicrystal (granting it 25 temporary HP as well); then manifest share pain on your Psicrystal so each of you split damage. Gives you the ability to Shrug off some serious punishment.

Combine with Stone Power from the Tome of Battle (allowing you to get an additional 10 temporary hp each round; which to my knowledge stacks with temporary Hp gained from other sources; at least it doesn't mention stacking problems in the Temporary HP section of the SRD when I checked), it allows you to shrug off obscene amounts of punishment.

You suck kind of offensively, but you can always grapple someone (touch attack) while Expanded and try to hold enemies while your party beats on them.