I love the 40g its the perfect dimensions and keeps my budget budgetable!
The lighting I got was the Nova Extreme 36" 156 watt 4 bulb fixture.
If you upgrade to a 40g GET IT DRILLED!!! If/when I ever move, while I have the tank dismantled I will have it drilled and keep everything in my frag tanks etc or put it all in a rubbermaid for the time being. I'm tired of worrying about my PVC overflow all the time etc.