Looking for a powerful but light image organization program

[Pugsworth]

I've been searching for a while now and I haven't been able to find an image organizer that suits my needs.

I've used picasa, lightroom, and digiKam (awful).
Picasa was the closest one to what I'm looking for, but it's still way behind.

I need a program that can quickly go through my images and allow me to add tags. This program needs to be nearly completely keyboard controllable.
The tagging system needs to use the image's metadata.
Not required, but it would be a huge plus if it also had a powerful sorting and searching system (like picasa). Online services are undesirable (flickr, etc).

To reiterate, the exact features I'm really looking for are:
* Full keyboard support
* Power tagging
* Easy image previewing (instead of just thumbnails)
* Saving to image metadata first, but database is fine as secondary

I would really appreciate if I could be helped with this situation.

[zman115]

Whats wrong with lightroom if I may ask?