LeXTAC is a versatile amplifier simulation.
Official Page (download is possible in the “amp sim pack”)
The demos linked on the site are down. If made a short demo, but it just catches one high gain setting!
You can turn all those sweet knobs and get various different sounds. Ranges from slightly disorted to in your face. It is suitable for many genres.
Looks close to but not quite like an amp.
Response is great, disortion versatile. The EQ is a little bit weak (you can hear it though) but this can be fixed by an instance of e.g. ReaEQ.
CPU load is only 1,8% – lower than most amp simulations I’ve used so far.