It's often my experience in metal that the bass guitar can be hard to really pick out in a band's sound. But recently I've come to really quite love some good bass work. 

It's easy for me to quickly jump to Iron Maiden's Steve Harris when thinking of metal bassists, but for my money the bass player I continually find myself most impressed by is Dominic "Forest" Lapointe who has been with acts such as Augury, Beyond Creation and First Fragment. He usually plays on a fretless and I especially love the sound of the fretless bass.

Here's some playthroughs of his:

And some songs:

I need to pay more attention to him, he was the first to bring the fretless sound to metal. I've obviously heard him in bands such as Death, but don't really know his body of work at all. 

Although Sadus may not be for everyone, you should at least give Swallowed in Black a chance. If only to hear how bass can also sound in thrash. His work with Death is of course legendary, but he has played in so many projects through the years.