Instead of doing rankings of whoever is the most ugly or hottest of the DW specialities, let's rank coolness/effectiveness/usefulness/overall viability of the Rank 5 prereq Psychic Powers (that includes Codex and Chapter powers).

So we got:
the gatey The Gate of Infinity,
the way too eye of terrorish Vortex of Doom,
the bloody Wings of Sanguinius,
the wormy Mind Worm,
Fury of the (Angry) Wolf Spirits,
the crushing Hammer of the Emperor and
the healing Glory of the Emperor.

Being the esteemed OP, I suppose I should start this off with my personal ranking. So let's see. I guess I value effectiveness/usefulness above the rest, so with that as a starting point, here goes:

1. The Gate of Infinity
2. Fury of the Wolf Spirits
3. Glory of the Emperor
4. Wings of Sanguinius
5. Mind Worm
6. Hammer of The Emperor
7. Vortex of Doom

Something like that I think. The pure practicality of the gate is quite nice, but the cooldown is rather bad. Should probably rank it a little lower due to that. Vortex of Doom is just too dangerous to be considered a standard weapon. Those corruption points would stack up fast, and creating a new eye of terror is probably not on the librarian's bucket list. Mind Worm seems a bit lackluster for a combat role, seeing as something solo will probably die rather fast anyway, and if it's the BBEG there's probably a high WP involved too.

Weighing them against each other was harder than I initially thought, I noticed.