Cordelia/Xander - Every time I see someone say how they were perfect for each other and how sad it was that Cordelia dumped him for good, I get angry. I'm sorry, but no; Xander cheated on Cordelia, I don't see how someone can watch that arc and still think Xander is the best choice for Cordelia. She deserves better than to be treated like that. Plus, I never got the feeling that Xander actually loved Cordy. He liked her, yes, and lusted after her; but if he loved her the way she loved him he never would have been tempted to cheat in the first place.
Cordelia/Wesley - They were obviously lusted after each other in Buffy season 3, but that was all there was to it. It was so unimportant that it was a non-issue on Angel.
Cordelia/Doyle - I think this pairing had the potential to eventually become something great, but unfortunately Doyle's time was tragically cut short. I think it they both cared deeply about each other (although it took Cordy a bit longer to clue in on that), but only knowing each other for two months... I can't say that it was love. They never really had the chance to get to know each other, which just makes it even sadder.
Cordelia/Groo. I don't much care for this pairing. Groo was a great guy, but he never really felt liked he belonged outside of Pylea. He was alright for Cordelia; I mean, he obviously loved her. But as she was unknowingly trying to make him more like Angel... I just can't see this pairing working.
Cordelia/Angel - This is the pairing that I choose. They had attraction, trust and respect. Angel could be difficult at times, but she never hesitated to call him out on his crap. As their friendship/relationship evolved, she was always able to make him smile. He was always much more animated and full of life due to her presence. Not to mention, unlike with Bangel, he actually had a personality with Cordelia. Plus, Angel even took time away from brooding go out of his way to show Cordelia how much he cared. He lost his way when she was in a coma, and when she awoke you could see how much happier, better, he is when she is around. They made the best of friends, and had the makings of the best of lovers. Too bad they never really had a shot. Those damn Higher Powers can never just mind their own business.