Welcome to the site and the hobby Jennifer.
Like Biff and David said,LEDs just aint all their cracked up to be right now.They have a tendency to burn out within a year or so.Plus the fixtures that I've seen personally,cause a spotlight effect,which IMO,just dont look good.
A good 4 foot fixture with 6 or 8 54 watt bulbs will be plenty of light for anything you want to keep in your tank.