Hi there,
If you are really going for a third party flash i would say the Nissin Di622 or the sunpak PZ42X. Both have mounts for nikon or canon, and from what i see Di622 is very easy to operate. Just on the flash,once the ready light is on you can fire away. There is auto focus, power 1:1 to 1:34(if i got the numbers correct) and it works with nikon I-TTL system,do check out some reviews about it. As for the sunpak PZ42X there is a LCD screen which you can tune your EV adjustments on it,but slightly less powerful than the Nissin. Nissin's guide number is 44 at ISO 100.
Hope this helps :thumbsup:
Cheers!
I just bought a snupak PZ42X from Edison Photos at Sim Lim yesterday. Not bad Flash for a newbie like me. I'm also using a D90. It auto colabarates according to your camera settings and when you zoom. Got it at $195