Try X-Japan - Blue Blood. Japanese speedmetal + hardrock + ballads, I really like the bass on that album. Check it out: Of course, the bassist has more breathing room in the slower songs.
Mr Bungle - Mr Bungle, Type O Negative - World Coming Down, Jane's Addiction - Ritual De Lo Habitual, Led Zeppelin - Presense
http://uk.youtube.com/watch?v=s2tIUzoQwcQ Gordian Knot is great (though it is not a conventional bass guitar).
First band, along with Virus, to come to mind for me. Then Ephel Duath. A fair bit of Akercocke has some awesome basslines too. And, whilst some may dislike them, Muse have some genius basswork.
I reckon gojira has some cool bass, its... rhytmical and I like it, check our their live DVD especially the song 'death of me'
Bands and album i know with good basswork Cynic ( Focus, Traced in Air ) Gordian knot ( Gordian knot, Emergent ) Spiral Architect ( A Sceptic's Universe ) Pavor ( Furioso ) Death ( Human, Individual Thought Patterns ) Ephel duath ( The Painter's Palette ) Riverside ( Out of Myself, Second Life Syndrome, Rapid Eye Movement ) Opeth ( Morning Rise , Ghost Reveries ) Augury ( Concealed )
Was going to mention this one. Very good. Also Spiral Architect, Spatic Ink and anything by John Patitucci.
The new Obscura Album - Cosmogenesis , also features some great (fretless) Bass-Work. Actually the bassist [Jeroen Paul Thesseling] was playing flamenco and world music before he joined obscura and that contributes a lot to the range of sound on the album. (Not only the Bass-work makes this album worth listening to... awesome high quality music.)