I concur on the T5, that is going to be too much. As for the LED, I have no direct experience with these, but from my reading I gather there are some very good lighting units available. Higher initial cost, but savings on the use (low energy) and longevity. As long as you get good planted tank units, and here I can't offer much. One thing to look for is the angle of the lens; many LED are 120 degree, which dissipates the light sideways. But those with 90 degrees are apparently well suited to aquaria. Then there is the issue of intensity.
The 24-36 inch Marineland has 12 1-watt LEDs, producing 600 lumens. This is good light, and better than a single T8. Now that I've seen this, I may well try it over my 29g. It lasts 5-6 years, which means no buying T8 tubes every year (which cost $22 here for this size) so that alone pays for the unit.
This unit also creates the effect of sun shining through water, which is something I've always appreciated when visitng the Vancouver Aquarium.
Not saying this is better, but it is worth considering in my view.