Probably I would recommend 25 watt Ceramic Metal Halide,
self-ballasted, with reflector (PAR) bulb. These would
look OK and brighten up the room with full-spectrum, non
spikey cheer-inducing light that is convenient to use. I
would suspend from the ceiling, and adjust the height.
These would cost about $100 each, retail. You might get
them wholesale for about $62.50. They are made by Philips.

You could also use compact fluorescents. These would be
cheaper, but the quality of light and ease of reflection
woudl be less.

What is the name of the plants? It looks like from the picture that these are shade plants, and you don't actually need any extra light at all. 25 w of CMH would be insignificant compared to the light you get coming in through those HUGE windows. I've just sowed 110 clivia seeds. That's another ideal indoor houseplant that does great with any light.
You might try going to the houseplant forum.
Lermer always recommends CMH, no matter what the question, and white paint as a reflector, he is a one note Johny that for some reason has not been banned by the administrator.
I think your plants will do just fine, don't worry, and do not over water, that's the most common reason for indoor plant failure. cheers.

The plants are:
Kangaroo Paw
Sago Palm
Zamioculcas zamiifolia

I live in the Seattle area so we have a lot of cloudy weather. From my reading the ZZ Plant should be OK (but it did have one stalk die from rotting under the soil surface even though I have had it one month and only watered once). I am worried about the kangaroo paw and the sago.

Thanks!

If you happen to have a dog, please be careful w/regard to the sago palm. These are toxic both to dogs and people. (I don't have the information about cats; maybe the ASPCA Poison Control folks can tell you.)

Cynthia H.
El Cerrito, CA (S.F. Bay Area)