I saw good chem with Hil and Chad in the motel scene in season 1 and I really hate LP. I didn't see much romantic/sexual chemistry between them after. I really thought Mark and the other writers were working towards a LP friendship but then all of sudden Peyton was back in love with Lucas.
I don't think Matthew Fox can have much sexual chem with anyone. I can see how someone can say that him and Evie have an amazing "connection" type chemistry. Some people just seem to do really well in sex scenes and have great chem with everyone and for other people, it's the complete opposite. Doing those type of scenes aren't easy. This is just my opinion of course. I might have a bias against Matthew because I find him and Jack really boring and they don't appeal to me.