I didn't hate Lindsey. I hated Lucas for putting her in the middle. Lucas was at fault for the L/L/Peyton fiasco. He was the one who was running from his lingering love/feelings for Peyton and tried to force himself to marry Lindsey. And when that didn't work he chased her relentlessly, even though Lindsey, recognizing and understanding Lucas better than he knew himself, walked away. I admire her for having the courage to do that, because she could've easily married Lucas and thrown it in Peyton's face, instead she was gracious when Peyton went to her to convince her to give Lucas another chance and she was the one to tell Peyton to read the book. Lindsey was the bigger person between the foreplay of Lucas/Peyton. She didn't do anything wrong, outside of reacting to Peyton's passive aggressive crap. (Let's be honest here, neither Peyton or Lindsey were exactly paragons of maturity in the library scene). I wasn't gungho about Lindsey, and I didn't feel all that bad about Lucas/Peyton, because Lindsey knew when she edited his book that Leyton was True Love Always and chose to date Lucas, even though it was quite obvious he had feelings for Peyton and always would. It was a risk she took and didn't work out for her. That's the risk we all take in life.
Overall, I found Lindsey to be the needed angst that drove all of season 5 for Lucas/Peyton and what led to season 6. So I'm glad she was there.