The older freeamp2 was a much deeper plugin that gave some systems problems, but I liked it a lot. Its down a little bit on the page.

The new freeamp3 does sound a little better, but offers less options and controls. I think you can get more than three FX slots going in it.

There is a helian bass amp sim that works pretty well also for free. Getting harder to find. It doesn't have much in the way of FX, but the amp/speaker sim makes a noticable difference.

I do not work here, but the benefits are still awesome
Make your sound your own!