Hey dude- you'll have to read a lot of reviews andf th eones on this site are very good. neogeoforlife is also a good resource.
BTW, Joe, Football Frenzy and the quiz games are pretty bad, the other people were pulling your chain.
A good title depends upon your likes, so here's a rundown:
expensive=$250 or less
cheap=$100 or less
Action:
Expensive: Metal Slug 3
Cheap: Cyber Lip
Shooter
Expensive: Viewpoint
Cheap: Last Resport
Fighting:
Expensive: Real Bout 2 or Real Bout Special
Cheap: Samurai Shodown II
Adventure:
Macigian Lord
Sports:
Expensive: Neo Turf Masters (golf)
Cheap: Baseball Stars 2
Sidescroll Beat-em-up:
Expensive: Sengoku 3
Cheap: Sengoku 2
Try a few of the above first, if you have the $ and like the Neo enough, here are a some titles I own that I LOVE, LOVE, LOVE, but they are rare a cost a lot of money:
Metal Slug X (action)
Blazing Star (shooter)
Pulstar (shooter)
Mark of the Wolves (fighting)
I hope this helps a bit. Also if you read a review, please note that many people use 7 or 70 as the average, so a lot of these games get an 8 or 80 and that means just a bit above average. When in doubt post a reply asking people fot their thoughts.