Not a big fan of her ME1 romance either. But for me, LotSB was what gave Liara's romance the depth that all ME2 romances lacked - there was conflict, resolution, and finally, you are able to reconcile the romance. The only other romance that comes close is Garrus'.
Except ME3 put the LotSB reconciliation romance into the gutter by not recognizing that you continued the romance in LotSB (you have to use Gibbed to properly correct the right romance flag) and for later giving Liara one of the most bulls**t Love Interest lines I've seen in this series:
Liara (on the Citadel): "I wish we could spend more time together like this... just friends...."
My FemShep: "... 'Just friends'... we banged after you took down the Broker in LotSB and I've made every romancable move on you since this third game started, but you think we're 'just friends'
F*** this, I'm gonna go replay ME2 and see just how much reach Garrus has."