I'm in the middle of trying to make a psionic character for an eberron game that is starting at level 2. My concept is a kalashtar orphan, and I'd like to make a gish-like (meaning fighter/mage) psionic character.
My first impulse was SoulKnife1/Psion1 (Nomad) and let's see what happens. Today I've been going through some of the builds, and sparked by the conversation, looking at the Wilder class specifically.
To cut to the chase, I'm dismayed by the Wilder class, to be honest. Their powers known number is abominable. I was stretching myself trying to find ways to shore up the weaknesses, but lets boil it down to the essentials:
You get 1 power per 'spell level'. The exceptions are 'spell level' 1 and 9, you get 2 powers for that 'spell level'. Expanded Knowledge is a great feat for Wilders, feat-starved or not they are supremely spell-starved.
Here are some potential Wilders at different levels:
Rayman
Human Wilder6, PB Shot, Precise Shot, Empower Power, Split Ray
Powers Known: Energy Ray, Vigor, Energy Push, Psionic Blast
Attack: +4
PP: 35 + Bonus Points
Typical Attack w/in 30 ft:
+5 touch attack w/ Energy Ray (Fire) using Wild Surge +2 against one opponent (6d6+7 [28 average] for 6 power points.
Alternately splitting the ray to two targets (6d6+7 x2 [approx 56 damage total]) for 6 Power Points (can use this at least 6 times in one day, but full-round to regain focus to split rays). Enervation chance: 10%
Tactics:
Nova and cross fingers no enervation. In the event he does run out of Power Points, makes an OK back-up crossbowman

. If things get hair and he needs to run, he can vigor up some big hp first. Basically a glass cannon though.
Future:
Power Specialization is a neat feat, but you have to pick up WF Rays to get it. Psionic Meditation is probably a better idea to get your focus back faster. There aren't any more good damaging rays until 'Disintegrate, Psionic' so this is one trick (or 2, with Energy Push) that may get old fast.
Kino
Elf Wilder9, Psicrystal, Psicrystal Containment, Expanded Knowledge - Energy Missile*, Privileged Energy
Powers Known: Energy Ray, Deceleration, Energy Stun, Solicit Psicrystal, Dimension Door, Psionic, and Energy Missile*
PP: 72 + Bonus Points
Typical Attack (Medium Range ~190-220 ft.):
Cold Energy Missiles using Wild Surge +3 and Privileged Energy (12d6+24 to up to 5 targets, DC 21 + Stat Mod Fortitude Save for Half [approx 66 per target if they fail]) for 9 power points. Can use this trick at least 8 times a day, Enervation chance: 15%
or
Short Range (40-55 ft.):
+6 (+Dexterity mod) ranged touch attack w/Cold Energy Ray using Wild Surge +3 and Privileged Energy (12d6+24 to one target, no save [66 damage]) for 9 power points. Enervation chance: 15%
Tactics:
Stay back and blast enemies that clump. Deceleration can help them stay back and Dimension Door can get you to a better position if they get close.
Future:
This kineticist in disguise is probably going for the Energy Current trick KarinsDad describes above (what with Solicit Psicrystal).
I'm not sure I calculated my numbers right, but these guys can dish it out, quickly and with little chance for error. They can also do it quite a few times per day. The correct comparison is not a barbarian, but a sorcerer. Here's a quick mock-up (and I'll be extra nice and level the Sorcerer to 7 so he gets an extra ray, otherwise you're comparing 4d6+1 to 6d6+7, possibly to 2 targets):
Scorch
Human Sor7, PB Shot, Precise Shot, ???, ???
Spells Known: 0-7, 1-4, 2-Scorching Ray, ???; 3-Fireball, ???
Spells/Day: 0-6, 1-7, 2-7, 3-5
Typical Attack w/in 30 ft:
+4 (+Dex mod) Scorching Ray (2 ranged attacks must be rolled) for 8d6+2 damage [30 average]. Can do this at most 7 times per day (unless he got a ridiculous Cha).
or
long range attack
7d6 damage in 20 ft radius (reflex save for half) [25 average].
I'm not going to redo the stats, but a Wilder gets Energy Surge +3 at 7th, as well as a BAB increase (so he can outdamage the sorcerer, barring enervation, and also has a higher chance to hit with his ranged touch attacks (but both are probably 90-95% anyway)).
Wow, that was really long. In short, Psionics can do some break-neck damage that you might not see coming (especially Wilders). Further, they can easily change the elemental type which sorcerers can't do until prestige classes, and they do outpace them damage-wise at a few different levels. They also have more skill points, hit points, a better BAB, and the ability to wear armor at the cost of less powers (and therefore utility).
So for a minor utility hit, play a wilder and do more damage than a sorcerer of equivalent level, most of the time (but be lucky with enervation rolls!

)