I am not sure If I am allowed to link to another site here, but this is a link to a nice calculator. It can calculate it for you easily...at least the min.
http://www.petfish.net/calculators/utankcalc.php
low to med light plants in a 5 gal should be 8W depending how deep-tall the tank is.
for med to high light plants you would need 19 or so W
This is for a standard 5 gallon.
I use the calculator cus i am horrid with numbers. xD You really shouldn't have any issues though with what you listed. IMHO it is more than enough.