[mstang1988]

1. Will 2GB of RAM be enough to just run Openelec?

Yes.

3. Should I go for a USB stick installation or a SSD? Is there much difference in speed between the two?

Yes there's a speed difference. Is it a "much" speed difference? It really depends on your personal preference.

USB sticks are cheap. Buy one and try it, if it turns out to be too slow for you, you can upgrade to an SSD later. Or if you have enough money that you don't care about 30-40 international currency units, buy an SSD straight off.

I agree, if you can afford it buy the SSD. I started mine using a USB 2.0 stick booted on my intel 847. It worked but the responsiveness and library updates were much faster with the SSD. Again, this was a USB 2.0 stick so YMMV.