Good effects
Control Flames: I'm surprised no one has mentioned this before. Sure, at low levels, it doesn't do much damage/creature/round, but over the lifetime of the spell and the number of potential creatures, the damage isn't too bad. For raw cost-effectiveness, it's probably the highest damage-dealer in the book (under ideal circumstances). It's also non-magical fire, so you can ignite things (houses, trees, monsters,...). At higher levels, it can be competative with spells several levels higher than its cost - note that its max damage increases with your caster level, not with the power points you put into it. It's power increases again if you get Solicit Psycrystal (assuming you have a psycrystal - if not, why not).
Crystal Shard: Popular, but again no one has mentioned it above (edit: oops- missed a comment). The big deal with this one is no SR, and no save. Other than that, it's a bit weak. You won't be complaining about that feature when you're up against a golem, or something with unusually high SR (Note that SR is less of a hindrance for a Psion than a Sorcerer, but immunity still sucks).
Force Screen: It lacks the best power of shield (immunity to MM), but otherwise it rocks. It means you probably will never buy a shield for an AC bonus.
Inertial Armor: You don't need to buy armor- and if you do, it won't be for the AC bonus (at caster LV 19 this gives the bonus of +5 ghost touch plate (with no check penalty)). Overchannel (or being a Wilder) obviously would give you higher bonuses at character level 19.
Precognition, Defensive: The AC bonus is just a minor side-benefit. The big deals here are two:
1) It can be cast as an immediate action. Great for when you've just seen a medusa.
2) It can pump your saves beyond reason. It even stacks with resistance
Vigor has a break I hadn't thought of before (I didn't vote for it; I probably should have):
1) Use Vigor.
2) Use a bunch of powers with Overchannel. Loose much of the Vigor temp HP.
3) Use Vigor.
You can also use it in place of Catfall. (actually, it's better as far as final HP are concerned). Just cast it up front.
I'll have to disagree with others on Mind Thrust. Sure, the damage is nice (as is the type of save), but your average opponent is still likely to have a reasonable save chance, and negates on a save. Unless you're good at guessing (or knowing) weak saves, we're talking roughly a 50/50 chance, which makes it comparable to Crystal shard (assuming no SR or immunity)
Skate and Catfall (mentioned by others above) are nice, but simular effects are cheap to get on magic items- I would be unlikely to actually get that power (save, possibly through Psychic Chirurgery.)
On the Discipline lists, I'll second several comments above that Astral Construct is extremely nice. Control Object is moderately nice.