I'm gonna build my second electric guitar in a few weeks and was thinking about the woods...
My first wass all maple but now i'm gonna experiment...

My question is:
Is it best to use a harder wood as the top and a softer wood in the back or the other way around?

I was thinkin a harder wood on top for a little bite to the sound and a soft wood in the back to add more midds and bass to the sound or is this just wrong thinking?

I know wood don't have that great effect to a electric as to a acoustic but i don't want to make a stupid mistake...

Thanks ahaed for the answers!
I wouldn't worry about it much. You should be more concerned about how it's put together and setup before you worry about something as insignificant as the minor differences in the density of different woods. A maple cap on mahogany is standard. There's a reason why guitar design doesn't change much. The old stuff works.
its all about the look and if its a super thin piece honestly I wouldn't worry about it. It's like going with a 0.008 high E to a 0.009 in regards to tone.

for transparent finishes though here's some ideas
cocobolo (mexican rosewood)
elm burl or any burl for that matter
quilted maple
figured maple
IIRC Gibson argue that the maple top and mahogany body contribute to the LP Standard tone. Although I'm really skeptical about such things, I think the all-mahogany construction of my LP Special contributes to its different tone from the maple-neck strat types. Maybe the neck is more important than the body as a contributor to tone? I personally would go for lightweight (eg chambered alder) and paint(eg strat, LP Jr) over tonal considerations and fancy timber, but I guess this is a minority view.