Well, to start with, you know that Lovespiralsdownward morphed into Lovespirals, right?
And I really dig that whole Elfenstaub series, although that's more downtempo than trip-hop
And Halou, Wiser always gets lumped in that trip-hop category, although it's more than that. One of my favourite albums of 2001, if not the favourite.
Rob Dougan, Furious Angels is similarly one of my favourite albums of 1998, though I didn't know that until years later. He, too, wanders outside of pure trip-hop. That's why I didn't want to recommend you anything, whatever I think of are my own albums of association more than what yours will be.
Blue Foundation, Sweep of Days
And of course there are the classics -- Becoming X, Faithless, Massive Attack, Morcheeba, Tricky, Portishead, Zero 7, Lamb (again: -ish)...
This is all assuming you're on Spotify and can try before you buy...I'm sure you have your own way of sampling stuff...
EDIT: Also, if you are on Spotify, I really like the playlist, "Enter the Dub" by Tom Grønås.