Yeah, the gecko was easy to assemble but is pretty heavy. I'd also get some heavy duty felt pads to put under it, as the studs that it comes with are usless... not as important if it's being installed onto carpet, but very important for wooden floors. I would say you'd need a little helper for the assembly.
As for the fans, I just got 4 ultra quiet fans from Maplin and a multi-voltage power supply, which I cut the end off and installed a molex connector. The fans can then just be connected with molex, like you would in a computer - selecting a smaller voltage than 12 volts, just makes the fans run slower (and quieter). I run mine at 9 volts. The main thing is to make sure the total amperage of the fans doesn't exceed the rating of the power supply. I stick them to the rack using white tack... as it insulates them from causing vibrations.
The amp... I just took it out of the box... no self assembly required

hehe!