AJ is probably the most consistant wrestler for putting on great matches. He always seems to be or have the highlight of the match. Sometimes its just because the guy can take an insane bump and never seem to get hurt (being pushed off a cage, i believe in his second Lethal Lockdown, or his insane spot on Ultimate X when he got dropkicked while hanging on the rope just to name a couple)
Any of the matches from when TNA first started. In 2003 I remember coming home from work and turning on ESPN Classic Canada and they were playing NWATNA right from the very beginning (only a year behind haha). I had always been a WWF/WWE guy, had no idea who any of the people were (had never heard of Jerry Lynn from ECW). But was just in awe of the X Division. Though Red and Loki were awesome, Styles just seemed to invent new moves every match and do things id never seen.
Early TNA
Styles vs Lynn
Styles vs Amazing Red
Styles vs Loki
Styles and Daniels vs AMW
Or any combination (triple threat/tag teams), including the first ever Xdivision match for the TNA Title. Or the Ladder match between Loki, Lynn and Styles.
Styles vs Abyss, he was always able to make Abyss actually look really good, and although small could pick Abyss up. Their first match at Lockdown is my favorite. They battle for a few minutes before even entering the ring, including a sick spot with the cage door.
Styles vs Daniels
Styles vs Joe
Once again, any combination, the triple threat being a highlight. Styles and Daniels work slower matt based matches while Styles and Joe seem to be fast paced and brutal. I remember them doing a partial "shoot" match where they didnt pull their hits as much. Styles thigh got a massive bruise from the steps during the match. I think they both ended up pretty bruised and battered.
While I never really caught much of ROH or indy stuff, one of my favorite matches ever was Styles vs Loki Vs Paul London in ROH.
Also check out Styles vs Matt Sydal (now Evan Bourne)