On geothermal, I dunno what the situation is in other countries, but here the biggest problem is that while we have all the required geology (Big hot granites with massive thick insulating sedimentay blankets on top) they're all way out in the desert, and the amount of energy you'd lose getting it back to major population centres makes it rarely economically viable. I think Adelaide is the only city where it has much chance of working, but, to be fair, they're well on their way towards getting that up and running. (Incidentally, the same sort of argument applies (In Australia) to these solar towers. We have the available land, it's just too far away from where we need the power. Of course, it'd be viable to power, say, smaller towns out in the desert or close to it.)
Even so, it (geothermal) wont solve our energy needs. I remember reading that even at maximum usage, we're only looking at a fairly small amount of our overall power consumption (just shy of 7% according to Wikipedia, which sounds about right).
Personally, I've always favoured a massively distributed power grid, with solar roof panels, wind turbines (off and onshore), tidal, hydro etc. etc. (all dependent on what you have available) with the occasional nuclear station around to supply baseload. So we still need nuclear.
